# File lib/active_record/associations.rb, line 765
      def has_many(association_id, options = {}, &extension)
        reflection = create_has_many_reflection(association_id, options, &extension)

        configure_dependency_for_has_many(reflection)

        add_multiple_associated_validation_callbacks(reflection.name) unless options[:validate] == false
        add_multiple_associated_save_callbacks(reflection.name)
        add_association_callbacks(reflection.name, reflection.options)

        if options[:through]
          collection_accessor_methods(reflection, HasManyThroughAssociation)
        else
          collection_accessor_methods(reflection, HasManyAssociation)
        end
      end