diff --git a/.rubocop.yml b/.rubocop.yml
index 138e863b..48e569cc 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -1,11 +1,19 @@
+# Load the rubocop-rspec gem
+require: rubocop-rspec
+
+Rails:
+  Enabled: true
 AllCops:
-  RunRailsCops: true
+  Exclude:
+    - lib/**/templates/*
+    - vendor/**/*
 
 #################
 # [i] Overrides #
 #################
 
-CollectionMethods:
+Style/CollectionMethods:
+  Enabled: true
   # Mapping from undesired method to desired_method
   # e.g. to use `detect` over `find`:
   #
@@ -13,34 +21,31 @@ CollectionMethods:
   #   PreferredMethods:
   #     find: detect
   PreferredMethods:
-    collect: 'map'
-    collect!: 'map!'
     reduce: 'inject'
-    find_all: 'select'
     find: 'detect'
+    each_with_index: 'each.with_index'
 
-# Multi-line method chaining should be done with leading dots.
-DotPosition:
-  EnforcedStyle: trailing
+Style/EmptyMethod:
+  EnforcedStyle: expanded
 
 # Align ends correctly.
 EndAlignment:
-  AlignWith: variable
-
-IfUnlessModifier:
-  MaxLineLength: 75
+  EnforcedStyleAlignWith: variable
 
 LineLength:
-  Max: 200
+  Max: 120
 
 SignalException:
   EnforcedStyle: only_raise
 
 SpaceInsideBlockBraces:
-  SpaceBeforeBlockParameters: false
+  SpaceBeforeBlockParameters: true
 
 SpaceInsideHashLiteralBraces:
-  EnforcedStyle: no_space
+  EnforcedStyle: space
+
+BracesAroundHashParameters:
+  EnforcedStyle: context_dependent
 
 StringLiterals:
   EnforcedStyle: double_quotes
@@ -48,44 +53,99 @@ StringLiterals:
 #################
 # Disabled cops #
 #################
-AbcSize:
+Metrics/ClassLength:
+  Enabled: false
+
+Metrics/CyclomaticComplexity:
+  Enabled: false
+
+Metrics/MethodLength:
   Enabled: false
 
-ClassAndModuleChildren:
+Style/ClassAndModuleChildren:
   Enabled: false
 
-ClassLength:
+Style/Documentation:
   Enabled: false
 
-CyclomaticComplexity:
+Style/EachWithObject:
   Enabled: false
 
-Documentation:
+Style/FormatString:
+  Enabled: false
+
+Style/Lambda:
+  Enabled: false
+
+Style/NegatedIf:
+  Enabled: false
+
+Style/PercentLiteralDelimiters:
+  PreferredDelimiters:
+    "%w": "[]"
+    "%W": "[]"
+    "%i": "[]"
+    "%I": "[]"
+
+Style/Semicolon:
   Enabled: false
 
-EachWithObject:
+Style/SingleLineBlockParams:
   Enabled: false
 
-FormatString:
+Style/WordArray:
   Enabled: false
 
-Lambda:
+# HABTM still has a place.
+# http://collectiveidea.com/blog/archives/2014/08/11/has_and_belongs_to_many-isnt-dead/
+Rails/HasAndBelongsToMany:
   Enabled: false
 
-MethodLength:
+# enforces using the class name in a describe block (e.g. `describe TestedClass do`)
+RSpec/DescribeClass:
   Enabled: false
 
-NegatedIf:
+# enforces using the described_class variablea (`described_class` instead of MyClass)
+RSpec/DescribedClass:
+  Enabled: false
+
+# RSpec examples are ok if they're long.
+# Explicitness is better than cleverness in tests.
+RSpec/ExampleLength:
+  Enabled: false
+
+# enforces using either `expect` or `allow` for stubs.  Since they do differnet things,
+# we should let the developer decide which to use
+RSpec/MessageExpectation:
+  Enabled: false
+
+# enforces having only one `expect` per test
+RSpec/MultipleExpectations:
+  Enabled: false
+
+# enforces rules about how many nested `describe` blocks are allowed
+RSpec/NestedGroups:
+  Enabled: false
+
+# enforces rules about using `it` or `describe` block methods instead of `feature` or `scenario`
+Capybara/FeatureMethods:
+  Enabled: false
+
+###################
+# Local overrides #
+###################
+
+Rails/ApplicationRecord:
   Enabled: false
 
-Semicolon:
+Rails/SkipsModelValidations:
   Enabled: false
 
-SingleLineBlockParams:
+Security/YAMLLoad:
   Enabled: false
 
-TrailingComma:
+Style/FormatStringToken:
   Enabled: false
 
-WordArray:
+Style/NumericPredicate:
   Enabled: false
diff --git a/.travis.yml b/.travis.yml
index 4b649387..88be7086 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -4,25 +4,27 @@ branches:
     - master
 before_script:
   - mysql -e 'create database delayed_job_test;'
+  - mysql --version
   - psql -c 'create database delayed_job_test;' -U postgres
-script: bundle exec rspec
+script: bundle exec $COMMAND
 env:
   global:
     - JRUBY_OPTS="$JRUBY_OPTS -Xcli.debug=true --debug"
+    - COMMAND=rspec
 gemfile: # Supported
   - gemfiles/mysql2/4-2.gemfile
-  - gemfiles/mysql2/5-0.gemfile
   - gemfiles/mysql2/5-1.gemfile
+  - gemfiles/mysql2/5-2.gemfile
   - gemfiles/postgresql/4-2.gemfile
-  - gemfiles/postgresql/5-0.gemfile
   - gemfiles/postgresql/5-1.gemfile
+  - gemfiles/postgresql/5-2.gemfile
   - gemfiles/sqlite3/4-2.gemfile
-  - gemfiles/sqlite3/5-0.gemfile
   - gemfiles/sqlite3/5-1.gemfile
+  - gemfiles/sqlite3/5-2.gemfile
 rvm: # Supported
-  - 2.2.7
-  - 2.3.4
-  - 2.4.1
+  - 2.2.10
+  - 2.3.7
+  - 2.4.4
   - jruby-9.1.8.0
 
 jdk: oraclejdk8
@@ -42,75 +44,112 @@ matrix:
       gemfile: gemfiles/mysql2/5-1.gemfile
     - rvm: jruby-9.1.8.0
       gemfile: gemfiles/postgresql/5-1.gemfile
+    - rvm: jruby-9.1.8.0
+      gemfile: gemfiles/mysql2/5-2.gemfile
+    - rvm: jruby-9.1.8.0
+      gemfile: gemfiles/postgresql/5-2.gemfile
+    - rvm: jruby-9.1.8.0
+      gemfile: gemfiles/sqlite3/5-2.gemfile
 
   include:
     #
+    # Rubocop
+    #
+    - rvm: 2.5.1
+      gemfile: Gemfile
+      env:
+        - COMMAND=rubocop
+    #
     # The future
     #
+    # MRI 2.5.1
+    - rvm: 2.5.1
+      gemfile: gemfiles/mysql2/5-1.gemfile
+    - rvm: 2.5.1
+      gemfile: gemfiles/postgresql/5-1.gemfile
+    - rvm: 2.5.1
+      gemfile: gemfiles/sqlite3/5-1.gemfile
+    - rvm: 2.5.1
+      gemfile: gemfiles/mysql2/5-2.gemfile
+    - rvm: 2.5.1
+      gemfile: gemfiles/postgresql/5-2.gemfile
+    - rvm: 2.5.1
+      gemfile: gemfiles/sqlite3/5-2.gemfile
     # Active Record head
-    - gemfile: gemfiles/mysql2/master.gemfile
-      rvm: 2.4.1
-    - gemfile: gemfiles/postgresql/master.gemfile
-      rvm: 2.4.1
-    - gemfile: gemfiles/sqlite3/master.gemfile
-      rvm: 2.4.1
+    - rvm: 2.5.1
+      gemfile: gemfiles/mysql2/master.gemfile
+    - rvm: 2.5.1
+      gemfile: gemfiles/postgresql/master.gemfile
+    - rvm: 2.5.1
+      gemfile: gemfiles/sqlite3/master.gemfile
     # MRI Ruby head
     - rvm: ruby-head
-      gemfile: gemfiles/mysql2/5-1.gemfile
+      gemfile: gemfiles/mysql2/5-2.gemfile
     - rvm: ruby-head
-      gemfile: gemfiles/postgresql/5-1.gemfile
+      gemfile: gemfiles/postgresql/5-2.gemfile
     - rvm: ruby-head
-      gemfile: gemfiles/sqlite3/5-1.gemfile
+      gemfile: gemfiles/sqlite3/5-2.gemfile
     # JRuby head
     - rvm: jruby-head
-      gemfile: gemfiles/mysql2/5-1.gemfile
+      gemfile: gemfiles/mysql2/5-2.gemfile
     - rvm: jruby-head
-      gemfile: gemfiles/postgresql/5-1.gemfile
+      gemfile: gemfiles/postgresql/5-2.gemfile
     - rvm: jruby-head
-      gemfile: gemfiles/sqlite3/5-1.gemfile
+      gemfile: gemfiles/sqlite3/5-2.gemfile
     #
     # The past
     #
     # EOL Active Record
-    - gemfile: gemfiles/mysql2/3-0.gemfile
-      rvm: 2.2.7
-    - gemfile: gemfiles/mysql2/3-1.gemfile
-      rvm: 2.2.7
-    - gemfile: gemfiles/mysql2/3-2.gemfile
-      rvm: 2.2.7
-    - gemfile: gemfiles/mysql2/4-0.gemfile
-      rvm: 2.3.4
-    - gemfile: gemfiles/mysql2/4-1.gemfile
-      rvm: 2.3.4
-    - gemfile: gemfiles/postgresql/3-0.gemfile
-      rvm: 2.2.7
-    - gemfile: gemfiles/postgresql/3-1.gemfile
-      rvm: 2.2.7
-    - gemfile: gemfiles/postgresql/3-2.gemfile
-      rvm: 2.2.7
-    - gemfile: gemfiles/postgresql/4-0.gemfile
-      rvm: 2.3.4
-    - gemfile: gemfiles/postgresql/4-1.gemfile
-      rvm: 2.3.4
-    - gemfile: gemfiles/sqlite3/3-0.gemfile
-      rvm: 2.2.7
-    - gemfile: gemfiles/sqlite3/3-1.gemfile
-      rvm: 2.2.7
-    - gemfile: gemfiles/sqlite3/3-2.gemfile
-      rvm: 2.2.7
-    - gemfile: gemfiles/sqlite3/4-0.gemfile
-      rvm: 2.3.4
-    - gemfile: gemfiles/sqlite3/4-1.gemfile
-      rvm: 2.3.4
+    # Rails 3.2 was maintained longer and is ruby 2.2 compatible
+    - rvm: 2.2.10
+      gemfile: gemfiles/mysql2/3-2.gemfile
+    - rvm: 2.2.10
+      gemfile: gemfiles/postgresql/3-2.gemfile
+    - rvm: 2.2.10
+      gemfile: gemfiles/sqlite3/3-2.gemfile
+    # Rails <= 4.0 was only compatible with ruby 2.0
+    # The test were running, but there are known incompatibilites
+    - rvm: 2.0.0-p648
+      gemfile: gemfiles/mysql2/3-0.gemfile
+    - rvm: 2.0.0-p648
+      gemfile: gemfiles/mysql2/3-1.gemfile
+    - rvm: 2.0.0-p648
+      gemfile: gemfiles/postgresql/3-0.gemfile
+    - rvm: 2.0.0-p648
+      gemfile: gemfiles/postgresql/3-1.gemfile
+    - rvm: 2.0.0-p648
+      gemfile: gemfiles/sqlite3/3-0.gemfile
+    - rvm: 2.0.0-p648
+      gemfile: gemfiles/sqlite3/3-1.gemfile
+    - rvm: 2.0.0-p648
+      gemfile: gemfiles/mysql2/4-0.gemfile
+    - rvm: 2.0.0-p648
+      gemfile: gemfiles/postgresql/4-0.gemfile
+    - rvm: 2.0.0-p648
+      gemfile: gemfiles/sqlite3/4-0.gemfile
+    # Rails 4.1 was only compatible with ruby 2.1
+    - rvm: 2.1.9
+      gemfile: gemfiles/mysql2/4-1.gemfile
+    - rvm: 2.1.9
+      gemfile: gemfiles/postgresql/4-1.gemfile
+    - rvm: 2.1.9
+      gemfile: gemfiles/sqlite3/4-1.gemfile
+    # Rails 5.0 was EOL with the release of 5.2
+    - rvm: 2.4.4
+      gemfile: gemfiles/mysql2/5-0.gemfile
+    - rvm: 2.4.4
+      gemfile: gemfiles/postgresql/5-0.gemfile
+    - rvm: 2.4.4
+      gemfile: gemfiles/sqlite3/5-0.gemfile
     #
     # The parallel dimension
     #
     # Rubinius
-    - gemfile: gemfiles/mysql2/5-1.gemfile
-      rvm: rbx-2
-    - gemfile: gemfiles/postgresql/5-1.gemfile
-      rvm: rbx-2
-    - gemfile: gemfiles/sqlite3/5-1.gemfile
-      rvm: rbx-2
+    - rvm: rbx-2
+      gemfile: gemfiles/mysql2/5-1.gemfile
+    - rvm: rbx-2
+      gemfile: gemfiles/postgresql/5-1.gemfile
+    - rvm: rbx-2
+      gemfile: gemfiles/sqlite3/5-1.gemfile
 
 sudo: false
diff --git a/Gemfile b/Gemfile
index 4ba62fec..6a063649 100644
--- a/Gemfile
+++ b/Gemfile
@@ -4,22 +4,21 @@ gem "rake"
 
 group :test do
   platforms :jruby do
-    gem 'activerecord-jdbcmysql-adapter', git: 'https://github.com/jruby/activerecord-jdbc-adapter', branch: 'rails-5'
-
-    gem 'activerecord-jdbcpostgresql-adapter', git: 'https://github.com/jruby/activerecord-jdbc-adapter', branch: 'rails-5'
-
-    gem 'activerecord-jdbcsqlite3-adapter', git: 'https://github.com/jruby/activerecord-jdbc-adapter', branch: 'rails-5'
+    gem "activerecord-jdbcmysql-adapter"
+    gem "activerecord-jdbcpostgresql-adapter"
+    gem "activerecord-jdbcsqlite3-adapter"
   end
 
   platforms :ruby, :mswin, :mingw do
-    gem 'mysql2', '~> 0.4.5'
-    gem "pg"
+    gem "mysql2", "~> 0.4.5"
+    gem "pg", "~> 0.18"
     gem "sqlite3"
   end
 
   gem "coveralls", require: false
   gem "rspec", ">= 3"
-  gem "rubocop", ">= 0.23"
+  gem "rubocop"
+  gem "rubocop-rspec"
   gem "simplecov", require: false
 end
 
diff --git a/README.md b/README.md
index 29598222..7e87f786 100644
--- a/README.md
+++ b/README.md
@@ -1,7 +1,7 @@
 **If you're viewing this at https://github.com/collectiveidea/delayed_job_active_record,
 you're reading the documentation for the master branch.
 [View documentation for the latest release
-(4.1.2).](https://github.com/collectiveidea/delayed_job_active_record/tree/v4.1.2)**
+(4.1.3).](https://github.com/collectiveidea/delayed_job_active_record/tree/v4.1.3)**
 
 # DelayedJob ActiveRecord Backend
 
diff --git a/Rakefile b/Rakefile
index d854d6fd..b8d3c778 100644
--- a/Rakefile
+++ b/Rakefile
@@ -3,7 +3,7 @@ Bundler::GemHelper.install_tasks
 
 require "rspec/core/rake_task"
 
-ADAPTERS = %w(mysql2 postgresql sqlite3)
+ADAPTERS = %w[mysql2 postgresql sqlite3].freeze
 
 ADAPTERS.each do |adapter|
   desc "Run RSpec code examples for #{adapter} adapter"
diff --git a/delayed_job_active_record.gemspec b/delayed_job_active_record.gemspec
index fffc38ce..f0c5f348 100644
--- a/delayed_job_active_record.gemspec
+++ b/delayed_job_active_record.gemspec
@@ -1,14 +1,14 @@
 Gem::Specification.new do |spec|
-  spec.add_dependency "activerecord", [">= 3.0", "< 5.2"]
+  spec.add_dependency "activerecord", [">= 3.0", "< 5.3"]
   spec.add_dependency "delayed_job",  [">= 3.0", "< 5"]
   spec.authors        = ["Brian Ryckbost", "Matt Griffin", "Erik Michaels-Ober"]
   spec.description    = "ActiveRecord backend for Delayed::Job, originally authored by Tobias Lütke"
   spec.email          = ["bryckbost@gmail.com", "matt@griffinonline.org", "sferik@gmail.com"]
-  spec.files          = %w(CONTRIBUTING.md LICENSE.md README.md delayed_job_active_record.gemspec) + Dir["lib/**/*.rb"]
+  spec.files          = %w[CONTRIBUTING.md LICENSE.md README.md delayed_job_active_record.gemspec] + Dir["lib/**/*.rb"]
   spec.homepage       = "http://github.com/collectiveidea/delayed_job_active_record"
   spec.licenses       = ["MIT"]
   spec.name           = "delayed_job_active_record"
   spec.require_paths  = ["lib"]
   spec.summary        = "ActiveRecord backend for DelayedJob"
-  spec.version        = "4.1.2"
+  spec.version        = "4.1.3"
 end
diff --git a/gemfiles/mysql2/3-0.gemfile b/gemfiles/mysql2/3-0.gemfile
index 19f3831c..836d9985 100644
--- a/gemfiles/mysql2/3-0.gemfile
+++ b/gemfiles/mysql2/3-0.gemfile
@@ -1,21 +1,15 @@
-source 'https://rubygems.org'
+source "https://rubygems.org"
 
-gem 'rake'
+gem "rake"
 
 group :test do
-  platforms :jruby do
-    gem 'activerecord-jdbcmysql-adapter'
-  end
+  gem "activerecord-mysql2-adapter"
 
-  platforms :ruby, :mswin, :mingw do
-    gem 'activerecord-mysql2-adapter'
-  end
+  gem "coveralls", require: false
+  gem "rspec", ">= 2.11"
+  gem "simplecov", require: false
 
-  gem 'coveralls', :require => false
-  gem 'rspec', '>= 2.11'
-  gem 'simplecov', :require => false
-
-  gem 'activerecord', "~> 3.0.0"
+  gem "activerecord", "~> 3.0.0"
 end
 
-gemspec :path => "../../"
+gemspec path: "../../"
diff --git a/gemfiles/mysql2/3-1.gemfile b/gemfiles/mysql2/3-1.gemfile
index a88d0791..5eb7ed81 100644
--- a/gemfiles/mysql2/3-1.gemfile
+++ b/gemfiles/mysql2/3-1.gemfile
@@ -1,22 +1,13 @@
-source 'https://rubygems.org'
+source "https://rubygems.org"
 
-gem 'rake'
+gem "rake"
 
-group :test do
-  platforms :jruby do
-    gem 'activerecord-jdbcmysql-adapter'
-  end
+gem "mysql2", "~> 0.3.10"
 
-  platforms :ruby, :mswin, :mingw do
-    gem 'mysql2', '~> 0.3.10'
-    gem 'activerecord-mysql2-adapter'
-  end
+gem "coveralls", require: false
+gem "rspec", ">= 2.11"
+gem "simplecov", require: false
 
-  gem 'coveralls', :require => false
-  gem 'rspec', '>= 2.11'
-  gem 'simplecov', :require => false
+gem "activerecord", "~> 3.1.0"
 
-  gem 'activerecord', "~> 3.1.0"
-end
-
-gemspec :path => "../../"
+gemspec path: "../../"
diff --git a/gemfiles/mysql2/3-2.gemfile b/gemfiles/mysql2/3-2.gemfile
index 2d60846d..2fd7011f 100644
--- a/gemfiles/mysql2/3-2.gemfile
+++ b/gemfiles/mysql2/3-2.gemfile
@@ -1,22 +1,13 @@
-source 'https://rubygems.org'
+source "https://rubygems.org"
 
-gem 'rake'
+gem "rake"
 
-group :test do
-  platforms :jruby do
-    gem 'activerecord-jdbcmysql-adapter'
-  end
+gem "mysql2", "~> 0.3.10"
 
-  platforms :ruby, :mswin, :mingw do
-    gem 'mysql2', '~> 0.3.10'
-    gem 'activerecord-mysql2-adapter'
-  end
+gem "coveralls", require: false
+gem "rspec", ">= 2.11"
+gem "simplecov", require: false
 
-  gem 'coveralls', :require => false
-  gem 'rspec', '>= 2.11'
-  gem 'simplecov', :require => false
+gem "activerecord", "~> 3.2.0"
 
-  gem 'activerecord', "~> 3.2.0"
-end
-
-gemspec :path => "../../"
+gemspec path: "../../"
diff --git a/gemfiles/mysql2/4-0.gemfile b/gemfiles/mysql2/4-0.gemfile
index 6a781b8f..a7720eb1 100644
--- a/gemfiles/mysql2/4-0.gemfile
+++ b/gemfiles/mysql2/4-0.gemfile
@@ -1,22 +1,13 @@
-source 'https://rubygems.org'
+source "https://rubygems.org"
 
-gem 'rake'
+gem "rake"
 
-group :test do
-  platforms :jruby do
-    gem 'activerecord-jdbcmysql-adapter'
-  end
+gem "mysql2", "~> 0.3.10"
 
-  platforms :ruby, :mswin, :mingw do
-    gem 'mysql2', '~> 0.3.10'
-    gem 'activerecord-mysql2-adapter'
-  end
+gem "coveralls", require: false
+gem "rspec", ">= 2.11"
+gem "simplecov", require: false
 
-  gem 'coveralls', :require => false
-  gem 'rspec', '>= 2.11'
-  gem 'simplecov', :require => false
+gem "activerecord", "~> 4.0.0"
 
-  gem 'activerecord', "~> 4.0.0"
-end
-
-gemspec :path => "../../"
+gemspec path: "../../"
diff --git a/gemfiles/mysql2/4-1.gemfile b/gemfiles/mysql2/4-1.gemfile
index f4c9aa7c..6f204a0e 100644
--- a/gemfiles/mysql2/4-1.gemfile
+++ b/gemfiles/mysql2/4-1.gemfile
@@ -1,22 +1,13 @@
-source 'https://rubygems.org'
+source "https://rubygems.org"
 
-gem 'rake'
+gem "rake"
 
-group :test do
-  platforms :jruby do
-    gem 'activerecord-jdbcmysql-adapter'
-  end
+gem "mysql2", "~> 0.3.13"
 
-  platforms :ruby, :mswin, :mingw do
-    gem 'mysql2', '~> 0.3.13'
-    gem 'activerecord-mysql2-adapter'
-  end
+gem "coveralls", require: false
+gem "rspec", ">= 2.11"
+gem "simplecov", require: false
 
-  gem 'coveralls', :require => false
-  gem 'rspec', '>= 2.11'
-  gem 'simplecov', :require => false
+gem "activerecord", "~> 4.1.0"
 
-  gem 'activerecord', "~> 4.1.0"
-end
-
-gemspec :path => "../../"
+gemspec path: "../../"
diff --git a/gemfiles/mysql2/4-2.gemfile b/gemfiles/mysql2/4-2.gemfile
index 24e9459e..7e633d79 100644
--- a/gemfiles/mysql2/4-2.gemfile
+++ b/gemfiles/mysql2/4-2.gemfile
@@ -1,21 +1,21 @@
-source 'https://rubygems.org'
+source "https://rubygems.org"
 
-gem 'rake'
+gem "rake"
 
 group :test do
   platforms :jruby do
-    gem 'activerecord-jdbcmysql-adapter'
+    gem "activerecord-jdbcmysql-adapter", "< 50.0"
   end
 
   platforms :ruby, :mswin, :mingw do
-    gem 'mysql2', '>= 0.3.13', '< 0.5'
+    gem "mysql2", ">= 0.3.13", "< 0.5"
   end
 
-  gem 'coveralls', :require => false
-  gem 'rspec', '>= 2.11'
-  gem 'simplecov', :require => false
+  gem "coveralls", require: false
+  gem "rspec", ">= 2.11"
+  gem "simplecov", require: false
 
-  gem 'activerecord', "~> 4.2.0"
+  gem "activerecord", "~> 4.2.0"
 end
 
-gemspec :path => "../../"
+gemspec path: "../../"
diff --git a/gemfiles/mysql2/5-0.gemfile b/gemfiles/mysql2/5-0.gemfile
index 6026756a..4c7d7d7d 100644
--- a/gemfiles/mysql2/5-0.gemfile
+++ b/gemfiles/mysql2/5-0.gemfile
@@ -1,21 +1,21 @@
-source 'https://rubygems.org'
+source "https://rubygems.org"
 
-gem 'rake'
+gem "rake"
 
 group :test do
   platforms :jruby do
-    gem 'activerecord-jdbcmysql-adapter', git: 'https://github.com/jruby/activerecord-jdbc-adapter', branch: 'rails-5'
+    gem "activerecord-jdbcmysql-adapter"
   end
 
   platforms :ruby, :mswin, :mingw do
-    gem 'mysql2'
+    gem "mysql2"
   end
 
-  gem 'coveralls', :require => false
-  gem 'rspec', '>= 2.11'
-  gem 'simplecov', :require => false
+  gem "coveralls", require: false
+  gem "rspec", ">= 2.11"
+  gem "simplecov", require: false
 
-  gem 'activerecord', "~> 5.0.0"
+  gem "activerecord", "~> 5.0.0"
 end
 
-gemspec :path => "../../"
+gemspec path: "../../"
diff --git a/gemfiles/mysql2/5-1.gemfile b/gemfiles/mysql2/5-1.gemfile
index bdec7686..249d3d2e 100644
--- a/gemfiles/mysql2/5-1.gemfile
+++ b/gemfiles/mysql2/5-1.gemfile
@@ -1,21 +1,21 @@
-source 'https://rubygems.org'
+source "https://rubygems.org"
 
-gem 'rake'
+gem "rake"
 
 group :test do
   platforms :jruby do
-    gem 'activerecord-jdbcmysql-adapter', git: 'https://github.com/jruby/activerecord-jdbc-adapter', branch: 'rails-5'
+    gem "activerecord-jdbcmysql-adapter"
   end
 
   platforms :ruby, :mswin, :mingw do
-    gem 'mysql2'
+    gem "mysql2"
   end
 
-  gem 'coveralls', :require => false
-  gem 'rspec', '>= 2.11'
-  gem 'simplecov', :require => false
+  gem "coveralls", require: false
+  gem "rspec", ">= 2.11"
+  gem "simplecov", require: false
 
-  gem 'activerecord', "~> 5.1.0"
+  gem "activerecord", "~> 5.1.0"
 end
 
-gemspec :path => "../../"
+gemspec path: "../../"
diff --git a/gemfiles/mysql2/5-2.gemfile b/gemfiles/mysql2/5-2.gemfile
new file mode 100644
index 00000000..ff77e119
--- /dev/null
+++ b/gemfiles/mysql2/5-2.gemfile
@@ -0,0 +1,21 @@
+source "https://rubygems.org"
+
+gem "rake"
+
+group :test do
+  platforms :jruby do
+    gem "activerecord-jdbcmysql-adapter"
+  end
+
+  platforms :ruby, :mswin, :mingw do
+    gem "mysql2"
+  end
+
+  gem "coveralls", require: false
+  gem "rspec", ">= 2.11"
+  gem "simplecov", require: false
+
+  gem "activerecord", "~> 5.2.0"
+end
+
+gemspec path: "../../"
diff --git a/gemfiles/mysql2/master.gemfile b/gemfiles/mysql2/master.gemfile
index 3c25e298..65659451 100644
--- a/gemfiles/mysql2/master.gemfile
+++ b/gemfiles/mysql2/master.gemfile
@@ -1,21 +1,21 @@
-source 'https://rubygems.org'
+source "https://rubygems.org"
 
-gem 'rake'
+gem "rake"
 
 group :test do
   platforms :jruby do
-    gem 'activerecord-jdbcmysql-adapter', git: 'https://github.com/jruby/activerecord-jdbc-adapter', branch: 'rails-5'
+    gem "activerecord-jdbcmysql-adapter"
   end
 
   platforms :ruby, :mswin, :mingw do
-    gem 'mysql2'
+    gem "mysql2"
   end
 
-  gem 'coveralls', :require => false
-  gem 'rspec', '>= 2.11'
-  gem 'simplecov', :require => false
+  gem "coveralls", require: false
+  gem "rspec", ">= 2.11"
+  gem "simplecov", require: false
 
-  gem 'activerecord', github: 'rails'
+  gem "activerecord", github: "rails"
 end
 
-gemspec :path => '../../'
+gemspec path: "../../"
diff --git a/gemfiles/postgresql/3-0.gemfile b/gemfiles/postgresql/3-0.gemfile
index 58a1c112..b46ce039 100644
--- a/gemfiles/postgresql/3-0.gemfile
+++ b/gemfiles/postgresql/3-0.gemfile
@@ -1,21 +1,15 @@
-source 'https://rubygems.org'
+source "https://rubygems.org"
 
-gem 'rake'
+gem "rake"
 
 group :test do
-  platforms :jruby do
-    gem 'activerecord-jdbcpostgresql-adapter'
-  end
+  gem "pg", "~> 0.18"
 
-  platforms :ruby, :mswin, :mingw do
-    gem 'pg'
-  end
+  gem "coveralls", require: false
+  gem "rspec", ">= 2.11"
+  gem "simplecov", require: false
 
-  gem 'coveralls', :require => false
-  gem 'rspec', '>= 2.11'
-  gem 'simplecov', :require => false
-
-  gem 'activerecord', "~> 3.0.0"
+  gem "activerecord", "~> 3.0.0"
 end
 
-gemspec :path => "../../"
+gemspec path: "../../"
diff --git a/gemfiles/postgresql/3-1.gemfile b/gemfiles/postgresql/3-1.gemfile
index 70f55e0c..4fb54b95 100644
--- a/gemfiles/postgresql/3-1.gemfile
+++ b/gemfiles/postgresql/3-1.gemfile
@@ -1,21 +1,15 @@
-source 'https://rubygems.org'
+source "https://rubygems.org"
 
-gem 'rake'
+gem "rake"
 
 group :test do
-  platforms :jruby do
-    gem 'activerecord-jdbcpostgresql-adapter'
-  end
+  gem "pg", "~> 0.18"
 
-  platforms :ruby, :mswin, :mingw do
-    gem 'pg'
-  end
+  gem "coveralls", require: false
+  gem "rspec", ">= 2.11"
+  gem "simplecov", require: false
 
-  gem 'coveralls', :require => false
-  gem 'rspec', '>= 2.11'
-  gem 'simplecov', :require => false
-
-  gem 'activerecord', "~> 3.1.0"
+  gem "activerecord", "~> 3.1.0"
 end
 
-gemspec :path => "../../"
+gemspec path: "../../"
diff --git a/gemfiles/postgresql/3-2.gemfile b/gemfiles/postgresql/3-2.gemfile
index ec77b087..e6ce602e 100644
--- a/gemfiles/postgresql/3-2.gemfile
+++ b/gemfiles/postgresql/3-2.gemfile
@@ -1,21 +1,15 @@
-source 'https://rubygems.org'
+source "https://rubygems.org"
 
-gem 'rake'
+gem "rake"
 
 group :test do
-  platforms :jruby do
-    gem 'activerecord-jdbcpostgresql-adapter'
-  end
+  gem "pg", "~> 0.18"
 
-  platforms :ruby, :mswin, :mingw do
-    gem 'pg'
-  end
+  gem "coveralls", require: false
+  gem "rspec", ">= 2.11"
+  gem "simplecov", require: false
 
-  gem 'coveralls', :require => false
-  gem 'rspec', '>= 2.11'
-  gem 'simplecov', :require => false
-
-  gem 'activerecord', "~> 3.2.0"
+  gem "activerecord", "~> 3.2.0"
 end
 
-gemspec :path => "../../"
+gemspec path: "../../"
diff --git a/gemfiles/postgresql/4-0.gemfile b/gemfiles/postgresql/4-0.gemfile
index c192aed2..31fba425 100644
--- a/gemfiles/postgresql/4-0.gemfile
+++ b/gemfiles/postgresql/4-0.gemfile
@@ -1,21 +1,15 @@
-source 'https://rubygems.org'
+source "https://rubygems.org"
 
-gem 'rake'
+gem "rake"
 
 group :test do
-  platforms :jruby do
-    gem 'activerecord-jdbcpostgresql-adapter'
-  end
+  gem "pg", "~> 0.18"
 
-  platforms :ruby, :mswin, :mingw do
-    gem 'pg'
-  end
+  gem "coveralls", require: false
+  gem "rspec", ">= 2.11"
+  gem "simplecov", require: false
 
-  gem 'coveralls', :require => false
-  gem 'rspec', '>= 2.11'
-  gem 'simplecov', :require => false
-
-  gem 'activerecord', "~> 4.0.0"
+  gem "activerecord", "~> 4.0.0"
 end
 
-gemspec :path => "../../"
+gemspec path: "../../"
diff --git a/gemfiles/postgresql/4-1.gemfile b/gemfiles/postgresql/4-1.gemfile
index af265cd6..278501c1 100644
--- a/gemfiles/postgresql/4-1.gemfile
+++ b/gemfiles/postgresql/4-1.gemfile
@@ -1,21 +1,15 @@
-source 'https://rubygems.org'
+source "https://rubygems.org"
 
-gem 'rake'
+gem "rake"
 
 group :test do
-  platforms :jruby do
-    gem 'activerecord-jdbcpostgresql-adapter'
-  end
+  gem "pg", "~> 0.18"
 
-  platforms :ruby, :mswin, :mingw do
-    gem 'pg'
-  end
+  gem "coveralls", require: false
+  gem "rspec", ">= 2.11"
+  gem "simplecov", require: false
 
-  gem 'coveralls', :require => false
-  gem 'rspec', '>= 2.11'
-  gem 'simplecov', :require => false
-
-  gem 'activerecord', "~> 4.1.0"
+  gem "activerecord", "~> 4.1.0"
 end
 
-gemspec :path => "../../"
+gemspec path: "../../"
diff --git a/gemfiles/postgresql/4-2.gemfile b/gemfiles/postgresql/4-2.gemfile
index eb042e60..047833e4 100644
--- a/gemfiles/postgresql/4-2.gemfile
+++ b/gemfiles/postgresql/4-2.gemfile
@@ -1,21 +1,21 @@
-source 'https://rubygems.org'
+source "https://rubygems.org"
 
-gem 'rake'
+gem "rake"
 
 group :test do
   platforms :jruby do
-    gem 'activerecord-jdbcpostgresql-adapter'
+    gem "activerecord-jdbcpostgresql-adapter", "< 50.0"
   end
 
   platforms :ruby, :mswin, :mingw do
-    gem 'pg'
+    gem "pg", "~> 0.18"
   end
 
-  gem 'coveralls', :require => false
-  gem 'rspec', '>= 2.11'
-  gem 'simplecov', :require => false
+  gem "coveralls", require: false
+  gem "rspec", ">= 2.11"
+  gem "simplecov", require: false
 
-  gem 'activerecord', "~> 4.2.0"
+  gem "activerecord", "~> 4.2.0"
 end
 
-gemspec :path => "../../"
+gemspec path: "../../"
diff --git a/gemfiles/postgresql/5-0.gemfile b/gemfiles/postgresql/5-0.gemfile
index ac3732f9..3c71ef69 100644
--- a/gemfiles/postgresql/5-0.gemfile
+++ b/gemfiles/postgresql/5-0.gemfile
@@ -1,21 +1,21 @@
-source 'https://rubygems.org'
+source "https://rubygems.org"
 
-gem 'rake'
+gem "rake"
 
 group :test do
   platforms :jruby do
-    gem 'activerecord-jdbcpostgresql-adapter', git: 'https://github.com/jruby/activerecord-jdbc-adapter', branch: 'rails-5'
+    gem "activerecord-jdbcpostgresql-adapter"
   end
 
   platforms :ruby, :mswin, :mingw do
-    gem 'pg'
+    gem "pg", "~> 0.18"
   end
 
-  gem 'coveralls', :require => false
-  gem 'rspec', '>= 2.11'
-  gem 'simplecov', :require => false
+  gem "coveralls", require: false
+  gem "rspec", ">= 2.11"
+  gem "simplecov", require: false
 
-  gem 'activerecord', "~> 5.0.0"
+  gem "activerecord", "~> 5.0.0"
 end
 
-gemspec :path => "../../"
+gemspec path: "../../"
diff --git a/gemfiles/postgresql/5-1.gemfile b/gemfiles/postgresql/5-1.gemfile
index 6b80728e..34e0c203 100644
--- a/gemfiles/postgresql/5-1.gemfile
+++ b/gemfiles/postgresql/5-1.gemfile
@@ -1,21 +1,21 @@
-source 'https://rubygems.org'
+source "https://rubygems.org"
 
-gem 'rake'
+gem "rake"
 
 group :test do
   platforms :jruby do
-    gem 'activerecord-jdbcpostgresql-adapter', git: 'https://github.com/jruby/activerecord-jdbc-adapter', branch: 'rails-5'
+    gem "activerecord-jdbcpostgresql-adapter"
   end
 
   platforms :ruby, :mswin, :mingw do
-    gem 'pg'
+    gem "pg", "~> 0.18"
   end
 
-  gem 'coveralls', :require => false
-  gem 'rspec', '>= 2.11'
-  gem 'simplecov', :require => false
+  gem "coveralls", require: false
+  gem "rspec", ">= 2.11"
+  gem "simplecov", require: false
 
-  gem 'activerecord', "~> 5.1.0"
+  gem "activerecord", "~> 5.1.0"
 end
 
-gemspec :path => "../../"
+gemspec path: "../../"
diff --git a/gemfiles/postgresql/5-2.gemfile b/gemfiles/postgresql/5-2.gemfile
new file mode 100644
index 00000000..e95902c7
--- /dev/null
+++ b/gemfiles/postgresql/5-2.gemfile
@@ -0,0 +1,21 @@
+source "https://rubygems.org"
+
+gem "rake"
+
+group :test do
+  platforms :jruby do
+    gem "activerecord-jdbcpostgresql-adapter"
+  end
+
+  platforms :ruby, :mswin, :mingw do
+    gem "pg", "~> 0.18"
+  end
+
+  gem "coveralls", require: false
+  gem "rspec", ">= 2.11"
+  gem "simplecov", require: false
+
+  gem "activerecord", "~> 5.2.0"
+end
+
+gemspec path: "../../"
diff --git a/gemfiles/postgresql/master.gemfile b/gemfiles/postgresql/master.gemfile
index ade52b13..7ac422ba 100644
--- a/gemfiles/postgresql/master.gemfile
+++ b/gemfiles/postgresql/master.gemfile
@@ -1,21 +1,21 @@
-source 'https://rubygems.org'
+source "https://rubygems.org"
 
-gem 'rake'
+gem "rake"
 
 group :test do
   platforms :jruby do
-    gem 'activerecord-jdbcpostgresql-adapter', git: 'https://github.com/jruby/activerecord-jdbc-adapter', branch: 'rails-5'
+    gem "activerecord-jdbcpostgresql-adapter"
   end
 
   platforms :ruby, :mswin, :mingw do
-    gem 'pg'
+    gem "pg", "~> 0.18"
   end
 
-  gem 'coveralls', :require => false
-  gem 'rspec', '>= 2.11'
-  gem 'simplecov', :require => false
+  gem "coveralls", require: false
+  gem "rspec", ">= 2.11"
+  gem "simplecov", require: false
 
-  gem 'activerecord', github: 'rails'
+  gem "activerecord", github: "rails"
 end
 
-gemspec :path => "../../"
+gemspec path: "../../"
diff --git a/gemfiles/sqlite3/3-0.gemfile b/gemfiles/sqlite3/3-0.gemfile
index 4b36e699..71b10b4e 100644
--- a/gemfiles/sqlite3/3-0.gemfile
+++ b/gemfiles/sqlite3/3-0.gemfile
@@ -1,21 +1,15 @@
-source 'https://rubygems.org'
+source "https://rubygems.org"
 
-gem 'rake'
+gem "rake"
 
 group :test do
-  platforms :jruby do
-    gem 'activerecord-jdbcsqlite3-adapter'
-  end
+  gem "sqlite3"
 
-  platforms :ruby, :mswin, :mingw do
-    gem 'sqlite3'
-  end
+  gem "coveralls", require: false
+  gem "rspec", ">= 2.11"
+  gem "simplecov", require: false
 
-  gem 'coveralls', :require => false
-  gem 'rspec', '>= 2.11'
-  gem 'simplecov', :require => false
-
-  gem 'activerecord', "~> 3.0.0"
+  gem "activerecord", "~> 3.0.0"
 end
 
-gemspec :path => "../../"
+gemspec path: "../../"
diff --git a/gemfiles/sqlite3/3-1.gemfile b/gemfiles/sqlite3/3-1.gemfile
index c27298ec..0099efad 100644
--- a/gemfiles/sqlite3/3-1.gemfile
+++ b/gemfiles/sqlite3/3-1.gemfile
@@ -1,21 +1,15 @@
-source 'https://rubygems.org'
+source "https://rubygems.org"
 
-gem 'rake'
+gem "rake"
 
 group :test do
-  platforms :jruby do
-    gem 'activerecord-jdbcsqlite3-adapter'
-  end
+  gem "sqlite3"
 
-  platforms :ruby, :mswin, :mingw do
-    gem 'sqlite3'
-  end
+  gem "coveralls", require: false
+  gem "rspec", ">= 2.11"
+  gem "simplecov", require: false
 
-  gem 'coveralls', :require => false
-  gem 'rspec', '>= 2.11'
-  gem 'simplecov', :require => false
-
-  gem 'activerecord', "~> 3.1.0"
+  gem "activerecord", "~> 3.1.0"
 end
 
-gemspec :path => "../../"
+gemspec path: "../../"
diff --git a/gemfiles/sqlite3/3-2.gemfile b/gemfiles/sqlite3/3-2.gemfile
index 974eba26..bb3394ea 100644
--- a/gemfiles/sqlite3/3-2.gemfile
+++ b/gemfiles/sqlite3/3-2.gemfile
@@ -1,21 +1,15 @@
-source 'https://rubygems.org'
+source "https://rubygems.org"
 
-gem 'rake'
+gem "rake"
 
 group :test do
-  platforms :jruby do
-    gem 'activerecord-jdbcsqlite3-adapter'
-  end
+  gem "sqlite3"
 
-  platforms :ruby, :mswin, :mingw do
-    gem 'sqlite3'
-  end
+  gem "coveralls", require: false
+  gem "rspec", ">= 2.11"
+  gem "simplecov", require: false
 
-  gem 'coveralls', :require => false
-  gem 'rspec', '>= 2.11'
-  gem 'simplecov', :require => false
-
-  gem 'activerecord', "~> 3.2.0"
+  gem "activerecord", "~> 3.2.0"
 end
 
-gemspec :path => "../../"
+gemspec path: "../../"
diff --git a/gemfiles/sqlite3/4-0.gemfile b/gemfiles/sqlite3/4-0.gemfile
index 15109853..ba3e3327 100644
--- a/gemfiles/sqlite3/4-0.gemfile
+++ b/gemfiles/sqlite3/4-0.gemfile
@@ -1,21 +1,15 @@
-source 'https://rubygems.org'
+source "https://rubygems.org"
 
-gem 'rake'
+gem "rake"
 
 group :test do
-  platforms :jruby do
-    gem 'activerecord-jdbcsqlite3-adapter'
-  end
+  gem "sqlite3"
 
-  platforms :ruby, :mswin, :mingw do
-    gem 'sqlite3'
-  end
+  gem "coveralls", require: false
+  gem "rspec", ">= 2.11"
+  gem "simplecov", require: false
 
-  gem 'coveralls', :require => false
-  gem 'rspec', '>= 2.11'
-  gem 'simplecov', :require => false
-
-  gem 'activerecord', "~> 4.0.0"
+  gem "activerecord", "~> 4.0.0"
 end
 
-gemspec :path => "../../"
+gemspec path: "../../"
diff --git a/gemfiles/sqlite3/4-1.gemfile b/gemfiles/sqlite3/4-1.gemfile
index 37cb391c..94a01013 100644
--- a/gemfiles/sqlite3/4-1.gemfile
+++ b/gemfiles/sqlite3/4-1.gemfile
@@ -1,21 +1,15 @@
-source 'https://rubygems.org'
+source "https://rubygems.org"
 
-gem 'rake'
+gem "rake"
 
 group :test do
-  platforms :jruby do
-    gem 'activerecord-jdbcsqlite3-adapter'
-  end
+  gem "sqlite3"
 
-  platforms :ruby, :mswin, :mingw do
-    gem 'sqlite3'
-  end
+  gem "coveralls", require: false
+  gem "rspec", ">= 2.11"
+  gem "simplecov", require: false
 
-  gem 'coveralls', :require => false
-  gem 'rspec', '>= 2.11'
-  gem 'simplecov', :require => false
-
-  gem 'activerecord', "~> 4.1.0"
+  gem "activerecord", "~> 4.1.0"
 end
 
-gemspec :path => "../../"
+gemspec path: "../../"
diff --git a/gemfiles/sqlite3/4-2.gemfile b/gemfiles/sqlite3/4-2.gemfile
index 2de1fe6a..a2ae2f44 100644
--- a/gemfiles/sqlite3/4-2.gemfile
+++ b/gemfiles/sqlite3/4-2.gemfile
@@ -1,21 +1,21 @@
-source 'https://rubygems.org'
+source "https://rubygems.org"
 
-gem 'rake'
+gem "rake"
 
 group :test do
   platforms :jruby do
-    gem 'activerecord-jdbcsqlite3-adapter'
+    gem "activerecord-jdbcsqlite3-adapter", "< 50.0"
   end
 
   platforms :ruby, :mswin, :mingw do
-    gem 'sqlite3'
+    gem "sqlite3"
   end
 
-  gem 'coveralls', :require => false
-  gem 'rspec', '>= 2.11'
-  gem 'simplecov', :require => false
+  gem "coveralls", require: false
+  gem "rspec", ">= 2.11"
+  gem "simplecov", require: false
 
-  gem 'activerecord', "~> 4.2.0"
+  gem "activerecord", "~> 4.2.0"
 end
 
-gemspec :path => "../../"
+gemspec path: "../../"
diff --git a/gemfiles/sqlite3/5-0.gemfile b/gemfiles/sqlite3/5-0.gemfile
index 4c2137ac..bc6e076c 100644
--- a/gemfiles/sqlite3/5-0.gemfile
+++ b/gemfiles/sqlite3/5-0.gemfile
@@ -1,21 +1,21 @@
-source 'https://rubygems.org'
+source "https://rubygems.org"
 
-gem 'rake'
+gem "rake"
 
 group :test do
   platforms :jruby do
-    gem 'activerecord-jdbcsqlite3-adapter', git: 'https://github.com/jruby/activerecord-jdbc-adapter', branch: 'rails-5'
+    gem "activerecord-jdbcsqlite3-adapter"
   end
 
   platforms :ruby, :mswin, :mingw do
-    gem 'sqlite3'
+    gem "sqlite3"
   end
 
-  gem 'coveralls', :require => false
-  gem 'rspec', '>= 2.11'
-  gem 'simplecov', :require => false
+  gem "coveralls", require: false
+  gem "rspec", ">= 2.11"
+  gem "simplecov", require: false
 
-  gem 'activerecord', "~> 5.0.0"
+  gem "activerecord", "~> 5.0.0"
 end
 
-gemspec :path => "../../"
+gemspec path: "../../"
diff --git a/gemfiles/sqlite3/5-1.gemfile b/gemfiles/sqlite3/5-1.gemfile
index 8f51461b..4c803830 100644
--- a/gemfiles/sqlite3/5-1.gemfile
+++ b/gemfiles/sqlite3/5-1.gemfile
@@ -1,21 +1,21 @@
-source 'https://rubygems.org'
+source "https://rubygems.org"
 
-gem 'rake'
+gem "rake"
 
 group :test do
   platforms :jruby do
-    gem 'activerecord-jdbcsqlite3-adapter', git: 'https://github.com/jruby/activerecord-jdbc-adapter', branch: 'rails-5'
+    gem "activerecord-jdbcsqlite3-adapter"
   end
 
   platforms :ruby, :mswin, :mingw do
-    gem 'sqlite3'
+    gem "sqlite3"
   end
 
-  gem 'coveralls', :require => false
-  gem 'rspec', '>= 2.11'
-  gem 'simplecov', :require => false
+  gem "coveralls", require: false
+  gem "rspec", ">= 2.11"
+  gem "simplecov", require: false
 
-  gem 'activerecord', "~> 5.1.0"
+  gem "activerecord", "~> 5.1.0"
 end
 
-gemspec :path => "../../"
+gemspec path: "../../"
diff --git a/gemfiles/sqlite3/5-2.gemfile b/gemfiles/sqlite3/5-2.gemfile
new file mode 100644
index 00000000..6dc5a0a0
--- /dev/null
+++ b/gemfiles/sqlite3/5-2.gemfile
@@ -0,0 +1,21 @@
+source "https://rubygems.org"
+
+gem "rake"
+
+group :test do
+  platforms :jruby do
+    gem "activerecord-jdbcsqlite3-adapter"
+  end
+
+  platforms :ruby, :mswin, :mingw do
+    gem "sqlite3"
+  end
+
+  gem "coveralls", require: false
+  gem "rspec", ">= 2.11"
+  gem "simplecov", require: false
+
+  gem "activerecord", "~> 5.2.0"
+end
+
+gemspec path: "../../"
diff --git a/gemfiles/sqlite3/master.gemfile b/gemfiles/sqlite3/master.gemfile
index 868fe561..afd2bf9a 100644
--- a/gemfiles/sqlite3/master.gemfile
+++ b/gemfiles/sqlite3/master.gemfile
@@ -1,21 +1,21 @@
-source 'https://rubygems.org'
+source "https://rubygems.org"
 
-gem 'rake'
+gem "rake"
 
 group :test do
   platforms :jruby do
-    gem 'activerecord-jdbcsqlite3-adapter', git: 'https://github.com/jruby/activerecord-jdbc-adapter', branch: 'rails-5'
+    gem "activerecord-jdbcsqlite3-adapter"
   end
 
   platforms :ruby, :mswin, :mingw do
-    gem 'sqlite3'
+    gem "sqlite3"
   end
 
-  gem 'coveralls', :require => false
-  gem 'rspec', '>= 2.11'
-  gem 'simplecov', :require => false
+  gem "coveralls", require: false
+  gem "rspec", ">= 2.11"
+  gem "simplecov", require: false
 
-  gem 'activerecord', github: 'rails'
+  gem "activerecord", github: "rails"
 end
 
-gemspec :path => "../../"
+gemspec path: "../../"
diff --git a/lib/delayed/backend/active_record.rb b/lib/delayed/backend/active_record.rb
index 5de99696..b69fd050 100644
--- a/lib/delayed/backend/active_record.rb
+++ b/lib/delayed/backend/active_record.rb
@@ -10,7 +10,9 @@ def initialize
         end
 
         def reserve_sql_strategy=(val)
-          raise ArgumentError, "allowed values are :optimized_sql or :default_sql" unless val == :optimized_sql || val == :default_sql
+          if !(val == :optimized_sql || val == :default_sql)
+            raise ArgumentError, "allowed values are :optimized_sql or :default_sql"
+          end
           @reserve_sql_strategy = val
         end
       end
@@ -34,6 +36,9 @@ class Job < ::ActiveRecord::Base
         end
 
         scope :by_priority, lambda { order("priority ASC, run_at ASC") }
+        scope :min_priority, lambda { where("priority >= ?", Worker.min_priority) if Worker.min_priority }
+        scope :max_priority, lambda { where("priority <= ?", Worker.max_priority) if Worker.max_priority }
+        scope :for_queues, lambda { |queues = Worker.queues| where(queue: queues) if Array(queues).any? }
 
         before_save :set_default_run_at
 
@@ -45,7 +50,12 @@ def self.set_delayed_job_table_name
         set_delayed_job_table_name
 
         def self.ready_to_run(worker_name, max_run_time)
-          where("(run_at <= ? AND (locked_at IS NULL OR locked_at < ?) OR locked_by = ?) AND failed_at IS NULL", db_time_now, db_time_now - max_run_time, worker_name)
+          where(
+            "(run_at <= ? AND (locked_at IS NULL OR locked_at < ?) OR locked_by = ?) AND failed_at IS NULL",
+            db_time_now,
+            db_time_now - max_run_time,
+            worker_name
+          )
         end
 
         def self.before_fork
@@ -61,15 +71,13 @@ def self.clear_locks!(worker_name)
           where(locked_by: worker_name).update_all(locked_by: nil, locked_at: nil)
         end
 
-        def self.reserve(worker, max_run_time = Worker.max_run_time) # rubocop:disable CyclomaticComplexity
-          # scope to filter to records that are "ready to run"
-          ready_scope = ready_to_run(worker.name, max_run_time)
-
-          # scope to filter to the single next eligible job
-          ready_scope = ready_scope.where("priority >= ?", Worker.min_priority) if Worker.min_priority
-          ready_scope = ready_scope.where("priority <= ?", Worker.max_priority) if Worker.max_priority
-          ready_scope = ready_scope.where(queue: Worker.queues) if Worker.queues.any?
-          ready_scope = ready_scope.by_priority
+        def self.reserve(worker, max_run_time = Worker.max_run_time)
+          ready_scope =
+            ready_to_run(worker.name, max_run_time)
+            .min_priority
+            .max_priority
+            .for_queues
+            .by_priority
 
           reserve_with_scope(ready_scope, worker, db_time_now)
         end
@@ -88,41 +96,12 @@ def self.reserve_with_scope(ready_scope, worker, now)
 
         def self.reserve_with_scope_using_optimized_sql(ready_scope, worker, now)
           case connection.adapter_name
-          when "PostgreSQL"
-            # Custom SQL required for PostgreSQL because postgres does not support UPDATE...LIMIT
-            # This locks the single record 'FOR UPDATE' in the subquery
-            # http://www.postgresql.org/docs/9.0/static/sql-select.html#SQL-FOR-UPDATE-SHARE
-            # Note: active_record would attempt to generate UPDATE...LIMIT like
-            # SQL for Postgres if we use a .limit() filter, but it would not
-            # use 'FOR UPDATE' and we would have many locking conflicts
-            quoted_table_name = connection.quote_table_name(table_name)
-            subquery_sql      = ready_scope.limit(1).lock(true).select("id").to_sql
-            reserved          = find_by_sql(["UPDATE #{quoted_table_name} SET locked_at = ?, locked_by = ? WHERE id IN (#{subquery_sql}) RETURNING *", now, worker.name])
-            reserved[0]
+          when "PostgreSQL", "PostGIS"
+            reserve_with_scope_using_optimized_postgres(ready_scope, worker, now)
           when "MySQL", "Mysql2"
-            # Removing the millisecond precision from now(time object)
-            # MySQL 5.6.4 onwards millisecond precision exists, but the
-            # datetime object created doesn't have precision, so discarded
-            # while updating. But during the where clause, for mysql(>=5.6.4),
-            # it queries with precision as well. So removing the precision
-            now = now.change(usec: 0)
-            # This works on MySQL and possibly some other DBs that support
-            # UPDATE...LIMIT. It uses separate queries to lock and return the job
-            count = ready_scope.limit(1).update_all(locked_at: now, locked_by: worker.name)
-            return nil if count == 0
-            where(locked_at: now, locked_by: worker.name, failed_at: nil).first
+            reserve_with_scope_using_optimized_mysql(ready_scope, worker, now)
           when "MSSQL", "Teradata"
-            # The MSSQL driver doesn't generate a limit clause when update_all
-            # is called directly
-            subsubquery_sql = ready_scope.limit(1).to_sql
-            # select("id") doesn't generate a subquery, so force a subquery
-            subquery_sql = "SELECT id FROM (#{subsubquery_sql}) AS x"
-            quoted_table_name = connection.quote_table_name(table_name)
-            sql = ["UPDATE #{quoted_table_name} SET locked_at = ?, locked_by = ? WHERE id IN (#{subquery_sql})", now, worker.name]
-            count = connection.execute(sanitize_sql(sql))
-            return nil if count == 0
-            # MSSQL JDBC doesn't support OUTPUT INSERTED.* for returning a result set, so query locked row
-            where(locked_at: now, locked_by: worker.name, failed_at: nil).first
+            reserve_with_scope_using_optimized_mssql(ready_scope, worker, now)
           # Fallback for unknown / other DBMS
           else
             reserve_with_scope_using_default_sql(ready_scope, worker, now)
@@ -137,6 +116,48 @@ def self.reserve_with_scope_using_default_sql(ready_scope, worker, now)
           end
         end
 
+        def self.reserve_with_scope_using_optimized_postgres(ready_scope, worker, now)
+          # Custom SQL required for PostgreSQL because postgres does not support UPDATE...LIMIT
+          # This locks the single record 'FOR UPDATE' in the subquery
+          # http://www.postgresql.org/docs/9.0/static/sql-select.html#SQL-FOR-UPDATE-SHARE
+          # Note: active_record would attempt to generate UPDATE...LIMIT like
+          # SQL for Postgres if we use a .limit() filter, but it would not
+          # use 'FOR UPDATE' and we would have many locking conflicts
+          quoted_name = connection.quote_table_name(table_name)
+          subquery    = ready_scope.limit(1).lock(true).select("id").to_sql
+          sql         = "UPDATE #{quoted_name} SET locked_at = ?, locked_by = ? WHERE id IN (#{subquery}) RETURNING *"
+          reserved    = find_by_sql([sql, now, worker.name])
+          reserved[0]
+        end
+
+        def self.reserve_with_scope_using_optimized_mysql(ready_scope, worker, now)
+          # Removing the millisecond precision from now(time object)
+          # MySQL 5.6.4 onwards millisecond precision exists, but the
+          # datetime object created doesn't have precision, so discarded
+          # while updating. But during the where clause, for mysql(>=5.6.4),
+          # it queries with precision as well. So removing the precision
+          now = now.change(usec: 0)
+          # This works on MySQL and possibly some other DBs that support
+          # UPDATE...LIMIT. It uses separate queries to lock and return the job
+          count = ready_scope.limit(1).update_all(locked_at: now, locked_by: worker.name)
+          return nil if count == 0
+          where(locked_at: now, locked_by: worker.name, failed_at: nil).first
+        end
+
+        def self.reserve_with_scope_using_optimized_mssql(ready_scope, worker, now)
+          # The MSSQL driver doesn't generate a limit clause when update_all
+          # is called directly
+          subsubquery_sql = ready_scope.limit(1).to_sql
+          # select("id") doesn't generate a subquery, so force a subquery
+          subquery_sql = "SELECT id FROM (#{subsubquery_sql}) AS x"
+          quoted_table_name = connection.quote_table_name(table_name)
+          sql = "UPDATE #{quoted_table_name} SET locked_at = ?, locked_by = ? WHERE id IN (#{subquery_sql})"
+          count = connection.execute(sanitize_sql([sql, now, worker.name]))
+          return nil if count == 0
+          # MSSQL JDBC doesn't support OUTPUT INSERTED.* for returning a result set, so query locked row
+          where(locked_at: now, locked_by: worker.name, failed_at: nil).first
+        end
+
         # Get the current time (GMT or local depending on DB)
         # Note: This does not ping the DB to get the time, so all your clients
         # must have syncronized clocks.
@@ -146,7 +167,7 @@ def self.db_time_now
           elsif ::ActiveRecord::Base.default_timezone == :utc
             Time.now.utc
           else
-            Time.now
+            Time.now # rubocop:disable Rails/TimeZone
           end
         end
 
diff --git a/lib/generators/delayed_job/active_record_generator.rb b/lib/generators/delayed_job/active_record_generator.rb
index ea4057ed..3370f06b 100644
--- a/lib/generators/delayed_job/active_record_generator.rb
+++ b/lib/generators/delayed_job/active_record_generator.rb
@@ -22,9 +22,7 @@ def self.next_migration_number(dirname)
     private
 
     def migration_version
-      if ActiveRecord::VERSION::MAJOR >= 5
-        "[#{ActiveRecord::VERSION::MAJOR}.#{ActiveRecord::VERSION::MINOR}]"
-      end
+      "[#{ActiveRecord::VERSION::MAJOR}.#{ActiveRecord::VERSION::MINOR}]" if ActiveRecord::VERSION::MAJOR >= 5
     end
   end
 end
diff --git a/lib/generators/delayed_job/upgrade_generator.rb b/lib/generators/delayed_job/upgrade_generator.rb
index c4425f16..2383f5ac 100644
--- a/lib/generators/delayed_job/upgrade_generator.rb
+++ b/lib/generators/delayed_job/upgrade_generator.rb
@@ -7,7 +7,11 @@
 module DelayedJob
   class UpgradeGenerator < ActiveRecordGenerator
     def create_migration_file
-      migration_template "upgrade_migration.rb", "db/migrate/add_queue_to_delayed_jobs.rb", migration_version: migration_version
+      migration_template(
+        "upgrade_migration.rb",
+        "db/migrate/add_queue_to_delayed_jobs.rb",
+        migration_version: migration_version
+      )
     end
   end
 end
diff --git a/spec/.rubocop.yml b/spec/.rubocop.yml
new file mode 100644
index 00000000..6c897e4d
--- /dev/null
+++ b/spec/.rubocop.yml
@@ -0,0 +1,14 @@
+inherit_from:
+  - ../.rubocop.yml
+
+Lint/AmbiguousBlockAssociation:
+  Enabled: false
+
+Metrics/BlockLength:
+  Enabled: false
+
+RSpec/ContextWording:
+  Enabled: false
+
+RSpec/FilePath:
+  Enabled: false
\ No newline at end of file
diff --git a/spec/delayed/backend/active_record_spec.rb b/spec/delayed/backend/active_record_spec.rb
index ad055f37..dd7bad96 100644
--- a/spec/delayed/backend/active_record_spec.rb
+++ b/spec/delayed/backend/active_record_spec.rb
@@ -6,27 +6,31 @@
 
   describe "configuration" do
     describe "reserve_sql_strategy" do
+      let(:configuration) { Delayed::Backend::ActiveRecord.configuration }
+
       it "allows :optimized_sql" do
-        Delayed::Backend::ActiveRecord.configuration.reserve_sql_strategy = :optimized_sql
-        expect(Delayed::Backend::ActiveRecord.configuration.reserve_sql_strategy).to eq(:optimized_sql)
+        configuration.reserve_sql_strategy = :optimized_sql
+        expect(configuration.reserve_sql_strategy).to eq(:optimized_sql)
       end
 
       it "allows :default_sql" do
-        Delayed::Backend::ActiveRecord.configuration.reserve_sql_strategy = :default_sql
-        expect(Delayed::Backend::ActiveRecord.configuration.reserve_sql_strategy).to eq(:default_sql)
+        configuration.reserve_sql_strategy = :default_sql
+        expect(configuration.reserve_sql_strategy).to eq(:default_sql)
       end
 
       it "raises an argument error on invalid entry" do
-        expect { Delayed::Backend::ActiveRecord.configuration.reserve_sql_strategy = :invald }.to raise_error(ArgumentError)
+        expect { configuration.reserve_sql_strategy = :invald }.to raise_error(ArgumentError)
       end
     end
   end
 
   describe "reserve_with_scope" do
-    let(:worker) { double(name: "worker01", read_ahead: 1) }
-    let(:scope)  { double(limit: limit, where: double(update_all: nil)) }
-    let(:limit)  { double(job: job, update_all: nil) }
-    let(:job)    { double(id: 1) }
+    let(:relation_class) { Delayed::Job.limit(1).class }
+    let(:worker) { instance_double(Delayed::Worker, name: "worker01", read_ahead: 1) }
+    let(:limit) { instance_double(relation_class, update_all: 0) }
+    let(:where) { instance_double(relation_class, update_all: 0) }
+    let(:scope) { instance_double(relation_class, limit: limit, where: where) }
+    let(:job) { instance_double(Delayed::Job, id: 1) }
 
     before do
       allow(Delayed::Backend::ActiveRecord::Job.connection).to receive(:adapter_name).at_least(:once).and_return(dbms)
@@ -40,8 +44,9 @@
         let(:dbms) { "MySQL" }
 
         it "uses the optimized sql version" do
-          expect(Delayed::Backend::ActiveRecord::Job).to_not receive(:reserve_with_scope_using_default_sql)
-          Delayed::Backend::ActiveRecord::Job.reserve_with_scope(scope, worker, Time.now)
+          allow(Delayed::Backend::ActiveRecord::Job).to receive(:reserve_with_scope_using_default_sql)
+          Delayed::Backend::ActiveRecord::Job.reserve_with_scope(scope, worker, Time.current)
+          expect(Delayed::Backend::ActiveRecord::Job).not_to have_received(:reserve_with_scope_using_default_sql)
         end
       end
 
@@ -49,8 +54,9 @@
         let(:dbms) { "OtherDB" }
 
         it "uses the plain sql version" do
-          expect(Delayed::Backend::ActiveRecord::Job).to receive(:reserve_with_scope_using_default_sql).once
-          Delayed::Backend::ActiveRecord::Job.reserve_with_scope(scope, worker, Time.now)
+          allow(Delayed::Backend::ActiveRecord::Job).to receive(:reserve_with_scope_using_default_sql)
+          Delayed::Backend::ActiveRecord::Job.reserve_with_scope(scope, worker, Time.current)
+          expect(Delayed::Backend::ActiveRecord::Job).to have_received(:reserve_with_scope_using_default_sql).once
         end
       end
     end
@@ -60,8 +66,9 @@
       let(:reserve_sql_strategy) { :default_sql }
 
       it "uses the plain sql version" do
-        expect(Delayed::Backend::ActiveRecord::Job).to receive(:reserve_with_scope_using_default_sql).once
-        Delayed::Backend::ActiveRecord::Job.reserve_with_scope(scope, worker, Time.now)
+        allow(Delayed::Backend::ActiveRecord::Job).to receive(:reserve_with_scope_using_default_sql)
+        Delayed::Backend::ActiveRecord::Job.reserve_with_scope(scope, worker, Time.current)
+        expect(Delayed::Backend::ActiveRecord::Job).to have_received(:reserve_with_scope_using_default_sql).once
       end
     end
   end
@@ -73,8 +80,8 @@
     end
 
     it "returns time in current time zone if set" do
-      Time.zone = "Eastern Time (US & Canada)"
-      expect(%(EST EDT)).to include(Delayed::Job.db_time_now.zone)
+      Time.zone = "Arizona"
+      expect(Delayed::Job.db_time_now.zone).to eq("MST")
     end
 
     it "returns UTC time if that is the AR default" do
@@ -84,16 +91,17 @@
     end
 
     it "returns local time if that is the AR default" do
-      Time.zone = "Central Time (US & Canada)"
+      Time.zone = "Arizona"
       ActiveRecord::Base.default_timezone = :local
-      expect(%w(CST CDT)).to include(Delayed::Backend::ActiveRecord::Job.db_time_now.zone)
+      expect(Delayed::Backend::ActiveRecord::Job.db_time_now.zone).to eq("MST")
     end
   end
 
   describe "after_fork" do
     it "calls reconnect on the connection" do
-      expect(ActiveRecord::Base).to receive(:establish_connection)
+      allow(ActiveRecord::Base).to receive(:establish_connection)
       Delayed::Backend::ActiveRecord::Job.after_fork
+      expect(ActiveRecord::Base).to have_received(:establish_connection)
     end
   end
 
@@ -112,12 +120,15 @@
       end
 
       after do
-        Delayed::Backend::ActiveRecord::Job.send(:attr_accessible, *Delayed::Backend::ActiveRecord::Job.new.attributes.keys)
+        Delayed::Backend::ActiveRecord::Job.send(
+          :attr_accessible,
+          *Delayed::Backend::ActiveRecord::Job.new.attributes.keys
+        )
       end
 
       it "is still accessible" do
         job = Delayed::Backend::ActiveRecord::Job.enqueue payload_object: EnqueueJobMod.new
-        expect(Delayed::Backend::ActiveRecord::Job.find(job.id).handler).to_not be_blank
+        expect(Delayed::Backend::ActiveRecord::Job.find(job.id).handler).not_to be_blank
       end
     end
   end
diff --git a/spec/helper.rb b/spec/helper.rb
index 63484664..80f3c280 100644
--- a/spec/helper.rb
+++ b/spec/helper.rb
@@ -1,10 +1,12 @@
 require "simplecov"
 require "coveralls"
 
-SimpleCov.formatter = SimpleCov::Formatter::MultiFormatter.new([
-  SimpleCov::Formatter::HTMLFormatter,
-  Coveralls::SimpleCov::Formatter
-])
+SimpleCov.formatter = SimpleCov::Formatter::MultiFormatter.new(
+  [
+    SimpleCov::Formatter::HTMLFormatter,
+    Coveralls::SimpleCov::Formatter
+  ]
+)
 
 SimpleCov.start do
   add_filter "/spec/"
@@ -24,7 +26,8 @@
 Delayed::Worker.logger = Logger.new("/tmp/dj.log")
 ENV["RAILS_ENV"] = "test"
 
-db_adapter, gemfile = ENV["ADAPTER"], ENV["BUNDLE_GEMFILE"]
+db_adapter = ENV["ADAPTER"]
+gemfile = ENV["BUNDLE_GEMFILE"]
 db_adapter ||= gemfile && gemfile[%r{gemfiles/(.*?)/}] && $1 # rubocop:disable PerlBackrefs
 db_adapter ||= "sqlite3"
 
@@ -36,22 +39,21 @@
 migration_template = File.open("lib/generators/delayed_job/templates/migration.rb")
 
 # need to eval the template with the migration_version intact
-migration_context = Class.new do
-  def get_binding
-    binding
-  end
+migration_context =
+  Class.new do
+    def my_binding
+      binding
+    end
 
-  private
+    private
 
-  def migration_version
-    if ActiveRecord::VERSION::MAJOR >= 5
-      "[#{ActiveRecord::VERSION::MAJOR}.#{ActiveRecord::VERSION::MINOR}]"
+    def migration_version
+      "[#{ActiveRecord::VERSION::MAJOR}.#{ActiveRecord::VERSION::MINOR}]" if ActiveRecord::VERSION::MAJOR >= 5
     end
   end
-end
 
-migration_ruby = ERB.new(migration_template.read).result(migration_context.new.get_binding)
-eval(migration_ruby)
+migration_ruby = ERB.new(migration_template.read).result(migration_context.new.my_binding)
+eval(migration_ruby) # rubocop:disable Security/Eval
 
 ActiveRecord::Schema.define do
   CreateDelayedJobs.up
@@ -73,8 +75,8 @@ def tell
     text
   end
 
-  def whatever(n, _)
-    tell * n
+  def whatever(number)
+    tell * number
   end
   default_scope { where(scoped: true) }