module ActiveModel::Serializer::Associations

def associations(include_directive = ActiveModelSerializers.default_include_directive)
  return unless object
  Enumerator.new do |y|
    self.class._reflections.each do |reflection|
      next if reflection.excluded?(self)
      key = reflection.options.fetch(:key, reflection.name)
      next unless include_directive.key?(key)
      y.yield reflection.build_association(self, instance_options)
    end
  end
end