initialize_attributes

# File activerecord/lib/active_record/associations/association.rb, line 166
      def initialize_attributes(record) #:nodoc:
        skip_assign = [reflection.foreign_key, reflection.type].compact
        attributes = create_scope.except(*(record.changed - skip_assign))
        record.assign_attributes(attributes)
        set_inverse_instance(record)
      end