Added PostGIS to the available addapters for reserve_with_scope method

lib/delayed/backend/active_record.rb

@@ -56,7 +56,7 @@ def self.reserve(worker, max_run_time = Worker.max_run_time) # rubocop:disable C
  def self.reserve_with_scope(ready_scope, worker, now)
  # Optimizations for faster lookups on some common databases
  case connection.adapter_name
- when "PostgreSQL"
+ when "PostgreSQL", "PostGIS"
  # Custom SQL required for PostgreSQL because postgres does not support UPDATE...LIMIT
  # This locks the single record 'FOR UPDATE' in the subquery
  # http:https://www.postgresql.org/docs/9.0/static/sql-select.html#SQL-FOR-UPDATE-SHARE