Use a real migration version number in docs

Even though this means more things to change when we bump after a
release, it's more important that our examples are directly copyable.

activerecord/README.rdoc

@@ -138,7 +138,7 @@ This would also define the following accessors: <tt>Product#name</tt> and
 
 * Database agnostic schema management with Migrations.
 
- class AddSystemSettings < ActiveRecord::Migration[0.0]
+ class AddSystemSettings < ActiveRecord::Migration[5.0]
  def up
  create_table :system_settings do |t|
  t.string :name

activerecord/lib/active_record/associations.rb

@@ -1639,7 +1639,7 @@ def belongs_to(name, scope = nil, options = {})
  # The join table should not have a primary key or a model associated with it. You must manually generate the
  # join table with a migration such as this:
  #
- # class CreateDevelopersProjectsJoinTable < ActiveRecord::Migration[0.0]
+ # class CreateDevelopersProjectsJoinTable < ActiveRecord::Migration[5.0]
  # def change
  # create_join_table :developers, :projects
  # end

activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb

@@ -190,7 +190,7 @@ def #{column_type}(*args, **options)
  # Inside migration files, the +t+ object in {create_table}[rdoc-ref:SchemaStatements#create_table]
  # is actually of this type:
  #
- # class SomeMigration < ActiveRecord::Migration[0.0]
+ # class SomeMigration < ActiveRecord::Migration[5.0]
  # def up
  # create_table :foo do |t|
  # puts t.class # => "ActiveRecord::ConnectionAdapters::TableDefinition"

activerecord/lib/active_record/migration.rb

@@ -13,7 +13,7 @@ def initialize(message = nil)
  # For example the following migration is not reversible.
  # Rolling back this migration will raise an ActiveRecord::IrreversibleMigration error.
  #
- # class IrreversibleMigrationExample < ActiveRecord::Migration[0.0]
+ # class IrreversibleMigrationExample < ActiveRecord::Migration[5.0]
  # def change
  # create_table :distributors do |t|
  # t.string :zipcode
@@ -31,7 +31,7 @@ def initialize(message = nil)
  #
  # 1. Define <tt>#up</tt> and <tt>#down</tt> methods instead of <tt>#change</tt>:
  #
- # class ReversibleMigrationExample < ActiveRecord::Migration[0.0]
+ # class ReversibleMigrationExample < ActiveRecord::Migration[5.0]
  # def up
  # create_table :distributors do |t|
  # t.string :zipcode
@@ -56,7 +56,7 @@ def initialize(message = nil)
  #
  # 2. Use the #reversible method in <tt>#change</tt> method:
  #
- # class ReversibleMigrationExample < ActiveRecord::Migration[0.0]
+ # class ReversibleMigrationExample < ActiveRecord::Migration[5.0]
  # def change
  # create_table :distributors do |t|
  # t.string :zipcode
@@ -155,7 +155,7 @@ def initialize(message = DEFAULT_MESSAGE)
  #
  # Example of a simple migration:
  #
- # class AddSsl < ActiveRecord::Migration[0.0]
+ # class AddSsl < ActiveRecord::Migration[5.0]
  # def up
  # add_column :accounts, :ssl_enabled, :boolean, default: true
  # end
@@ -175,7 +175,7 @@ def initialize(message = DEFAULT_MESSAGE)
  #
  # Example of a more complex migration that also needs to initialize data:
  #
- # class AddSystemSettings < ActiveRecord::Migration[0.0]
+ # class AddSystemSettings < ActiveRecord::Migration[5.0]
  # def up
  # create_table :system_settings do |t|
  # t.string :name
@@ -301,7 +301,7 @@ def initialize(message = DEFAULT_MESSAGE)
  # rails generate migration add_fieldname_to_tablename fieldname:string
  #
  # This will generate the file <tt>timestamp_add_fieldname_to_tablename.rb</tt>, which will look like this:
- # class AddFieldnameToTablename < ActiveRecord::Migration[0.0]
+ # class AddFieldnameToTablename < ActiveRecord::Migration[5.0]
  # def change
  # add_column :tablenames, :fieldname, :string
  # end
@@ -332,7 +332,7 @@ def initialize(message = DEFAULT_MESSAGE)
  #
  # Not all migrations change the schema. Some just fix the data:
  #
- # class RemoveEmptyTags < ActiveRecord::Migration[0.0]
+ # class RemoveEmptyTags < ActiveRecord::Migration[5.0]
  # def up
  # Tag.all.each { |tag| tag.destroy if tag.pages.empty? }
  # end
@@ -345,7 +345,7 @@ def initialize(message = DEFAULT_MESSAGE)
  #
  # Others remove columns when they migrate up instead of down:
  #
- # class RemoveUnnecessaryItemAttributes < ActiveRecord::Migration[0.0]
+ # class RemoveUnnecessaryItemAttributes < ActiveRecord::Migration[5.0]
  # def up
  # remove_column :items, :incomplete_items_count
  # remove_column :items, :completed_items_count
@@ -359,7 +359,7 @@ def initialize(message = DEFAULT_MESSAGE)
  #
  # And sometimes you need to do something in SQL not abstracted directly by migrations:
  #
- # class MakeJoinUnique < ActiveRecord::Migration[0.0]
+ # class MakeJoinUnique < ActiveRecord::Migration[5.0]
  # def up
  # execute "ALTER TABLE `pages_linked_pages` ADD UNIQUE `page_id_linked_page_id` (`page_id`,`linked_page_id`)"
  # end
@@ -376,7 +376,7 @@ def initialize(message = DEFAULT_MESSAGE)
  # <tt>Base#reset_column_information</tt> in order to ensure that the model has the
  # latest column data from after the new column was added. Example:
  #
- # class AddPeopleSalary < ActiveRecord::Migration[0.0]
+ # class AddPeopleSalary < ActiveRecord::Migration[5.0]
  # def up
  # add_column :people, :salary, :integer
  # Person.reset_column_information
@@ -434,7 +434,7 @@ def initialize(message = DEFAULT_MESSAGE)
  # To define a reversible migration, define the +change+ method in your
  # migration like this:
  #
- # class TenderloveMigration < ActiveRecord::Migration[0.0]
+ # class TenderloveMigration < ActiveRecord::Migration[5.0]
  # def change
  # create_table(:horses) do |t|
  # t.column :content, :text
@@ -464,7 +464,7 @@ def initialize(message = DEFAULT_MESSAGE)
  # can't execute inside a transaction though, and for these situations
  # you can turn the automatic transactions off.
  #
- # class ChangeEnum < ActiveRecord::Migration[0.0]
+ # class ChangeEnum < ActiveRecord::Migration[5.0]
  # disable_ddl_transaction!
  #
  # def up
@@ -605,7 +605,7 @@ def initialize(name = self.class.name, version = nil)
  # and create the table 'apples' on the way up, and the reverse
  # on the way down.
  #
- # class FixTLMigration < ActiveRecord::Migration[0.0]
+ # class FixTLMigration < ActiveRecord::Migration[5.0]
  # def change
  # revert do
  # create_table(:horses) do |t|
@@ -624,7 +624,7 @@ def initialize(name = self.class.name, version = nil)
  #
  # require_relative '20121212123456_tenderlove_migration'
  #
- # class FixupTLMigration < ActiveRecord::Migration[0.0]
+ # class FixupTLMigration < ActiveRecord::Migration[5.0]
  # def change
  # revert TenderloveMigration
  #
@@ -677,7 +677,7 @@ def down
  # when the three columns 'first_name', 'last_name' and 'full_name' exist,
  # even when migrating down:
  #
- # class SplitNameMigration < ActiveRecord::Migration[0.0]
+ # class SplitNameMigration < ActiveRecord::Migration[5.0]
  # def change
  # add_column :users, :first_name, :string
  # add_column :users, :last_name, :string

activerecord/lib/active_record/model_schema.rb

@@ -275,7 +275,7 @@ def content_columns
  # when just after creating a table you want to populate it with some default
  # values, eg:
  #
- # class CreateJobLevels < ActiveRecord::Migration[0.0]
+ # class CreateJobLevels < ActiveRecord::Migration[5.0]
  # def up
  # create_table :job_levels do |t|
  # t.integer :id

guides/source/active_record_basics.md

@@ -350,7 +350,7 @@ database that Active Record supports using `rake`. Here's a migration that
 creates a table:
 
 ```ruby
-class CreatePublications < ActiveRecord::Migration[0.0]
+class CreatePublications < ActiveRecord::Migration[5.0]
  def change
  create_table :publications do |t|
  t.string :title

guides/source/active_record_migrations.md

@@ -35,7 +35,7 @@ history to the latest version. Active Record will also update your
 Here's an example of a migration:
 
 ```ruby
-class CreateProducts < ActiveRecord::Migration[0.0]
+class CreateProducts < ActiveRecord::Migration[5.0]
  def change
  create_table :products do |t|
  t.string :name
@@ -72,7 +72,7 @@ If you wish for a migration to do something that Active Record doesn't know how
 to reverse, you can use `reversible`:
 
 ```ruby
-class ChangeProductsPrice < ActiveRecord::Migration[0.0]
+class ChangeProductsPrice < ActiveRecord::Migration[5.0]
  def change
  reversible do |dir|
  change_table :products do |t|
@@ -87,7 +87,7 @@ end
 Alternatively, you can use `up` and `down` instead of `change`:
 
 ```ruby
-class ChangeProductsPrice < ActiveRecord::Migration[0.0]
+class ChangeProductsPrice < ActiveRecord::Migration[5.0]
  def up
  change_table :products do |t|
  t.change :price, :string
@@ -129,7 +129,7 @@ $ bin/rails generate migration AddPartNumberToProducts
 This will create an empty but appropriately named migration:
 
 ```ruby
-class AddPartNumberToProducts < ActiveRecord::Migration[0.0]
+class AddPartNumberToProducts < ActiveRecord::Migration[5.0]
  def change
  end
 end
@@ -146,7 +146,7 @@ $ bin/rails generate migration AddPartNumberToProducts part_number:string
 will generate
 
 ```ruby
-class AddPartNumberToProducts < ActiveRecord::Migration[0.0]
+class AddPartNumberToProducts < ActiveRecord::Migration[5.0]
  def change
  add_column :products, :part_number, :string
  end
@@ -162,7 +162,7 @@ $ bin/rails generate migration AddPartNumberToProducts part_number:string:index
 will generate
 
 ```ruby
-class AddPartNumberToProducts < ActiveRecord::Migration[0.0]
+class AddPartNumberToProducts < ActiveRecord::Migration[5.0]
  def change
  add_column :products, :part_number, :string
  add_index :products, :part_number
@@ -180,7 +180,7 @@ $ bin/rails generate migration RemovePartNumberFromProducts part_number:string
 generates
 
 ```ruby
-class RemovePartNumberFromProducts < ActiveRecord::Migration[0.0]
+class RemovePartNumberFromProducts < ActiveRecord::Migration[5.0]
  def change
  remove_column :products, :part_number, :string
  end
@@ -196,7 +196,7 @@ $ bin/rails generate migration AddDetailsToProducts part_number:string price:dec
 generates
 
 ```ruby
-class AddDetailsToProducts < ActiveRecord::Migration[0.0]
+class AddDetailsToProducts < ActiveRecord::Migration[5.0]
  def change
  add_column :products, :part_number, :string
  add_column :products, :price, :decimal
@@ -215,7 +215,7 @@ $ bin/rails generate migration CreateProducts name:string part_number:string
 generates
 
 ```ruby
-class CreateProducts < ActiveRecord::Migration[0.0]
+class CreateProducts < ActiveRecord::Migration[5.0]
  def change
  create_table :products do |t|
  t.string :name
@@ -239,7 +239,7 @@ $ bin/rails generate migration AddUserRefToProducts user:references
 generates
 
 ```ruby
-class AddUserRefToProducts < ActiveRecord::Migration[0.0]
+class AddUserRefToProducts < ActiveRecord::Migration[5.0]
  def change
  add_reference :products, :user, index: true, foreign_key: true
  end
@@ -257,7 +257,7 @@ $ bin/rails g migration CreateJoinTableCustomerProduct customer product
 will produce the following migration:
 
 ```ruby
-class CreateJoinTableCustomerProduct < ActiveRecord::Migration[0.0]
+class CreateJoinTableCustomerProduct < ActiveRecord::Migration[5.0]
  def change
  create_join_table :customers, :products do |t|
  # t.index [:customer_id, :product_id]
@@ -281,7 +281,7 @@ $ bin/rails generate model Product name:string description:text
 will create a migration that looks like this
 
 ```ruby
-class CreateProducts < ActiveRecord::Migration[0.0]
+class CreateProducts < ActiveRecord::Migration[5.0]
  def change
  create_table :products do |t|
  t.string :name
@@ -309,7 +309,7 @@ $ bin/rails generate migration AddDetailsToProducts 'price:decimal{5,2}' supplie
 will produce a migration that looks like this
 
 ```ruby
-class AddDetailsToProducts < ActiveRecord::Migration[0.0]
+class AddDetailsToProducts < ActiveRecord::Migration[5.0]
  def change
  add_column :products, :price, :decimal, precision: 5, scale: 2
  add_reference :products, :supplier, polymorphic: true, index: true
@@ -563,7 +563,7 @@ to reverse. You can use `reversible` to specify what to do when running a
 migration and what else to do when reverting it. For example:
 
 ```ruby
-class ExampleMigration < ActiveRecord::Migration[0.0]
+class ExampleMigration < ActiveRecord::Migration[5.0]
  def change
  create_table :distributors do |t|
  t.string :zipcode
@@ -616,7 +616,7 @@ is wise to perform the transformations in precisely the reverse order they were
 made in the `up` method. The example in the `reversible` section is equivalent to:
 
 ```ruby
-class ExampleMigration < ActiveRecord::Migration[0.0]
+class ExampleMigration < ActiveRecord::Migration[5.0]
  def up
  create_table :distributors do |t|
  t.string :zipcode
@@ -659,7 +659,7 @@ You can use Active Record's ability to rollback migrations using the `revert` me
 ```ruby
 require_relative '20121212123456_example_migration'
 
-class FixupExampleMigration < ActiveRecord::Migration[0.0]
+class FixupExampleMigration < ActiveRecord::Migration[5.0]
  def change
  revert ExampleMigration
 
@@ -677,7 +677,7 @@ is later decided it would be best to use Active Record validations,
 in place of the `CHECK` constraint, to verify the zipcode.
 
 ```ruby
-class DontUseConstraintForZipcodeValidationMigration < ActiveRecord::Migration[0.0]
+class DontUseConstraintForZipcodeValidationMigration < ActiveRecord::Migration[5.0]
  def change
  revert do
  # copy-pasted code from ExampleMigration
@@ -841,7 +841,7 @@ Several methods are provided in migrations that allow you to control all this:
 For example, this migration:
 
 ```ruby
-class CreateProducts < ActiveRecord::Migration[0.0]
+class CreateProducts < ActiveRecord::Migration[5.0]
  def change
  suppress_messages do
  create_table :products do |t|
@@ -1015,7 +1015,7 @@ to add or modify data. This is useful in an existing database that can't be dest
 and recreated, such as a production database. 
 
 ```ruby
-class AddInitialProducts < ActiveRecord::Migration[0.0]
+class AddInitialProducts < ActiveRecord::Migration[5.0]
  def up
  5.times do |i|
  Product.create(name: "Product ##{i}", description: "A product.")