class ActiveModel::Serializer::Associations::Config

def self.refine(name, class_options)
  current_class = self
  Class.new(self) do
    singleton_class.class_eval do
      define_method(:to_s) do
        "(subclass of #{current_class.name})"
      end
      alias inspect to_s
    end
    self.options = class_options
  end
end