# File lib/active_record/associations.rb, line 666
      def has_many(association_id, options = {}, &extension)
        reflection = create_has_many_reflection(association_id, options, &extension)

        configure_dependency_for_has_many(reflection)

        if options[:through]
          collection_reader_method(reflection, HasManyThroughAssociation)
          collection_accessor_methods(reflection, HasManyThroughAssociation, false)
        else
          add_multiple_associated_save_callbacks(reflection.name)
          add_association_callbacks(reflection.name, reflection.options)
          collection_accessor_methods(reflection, HasManyAssociation)
        end
      end