lib/active_record/events.rb
require 'active_support'
require 'active_record/events/version'
require 'active_record/events/naming'
require 'active_record/events/method_factory'
require 'active_record/events/extension'
require 'active_record/events/macro'
ActiveSupport.on_load(:active_record) do
extend ActiveRecord::Events::Extension
end