It's my reminder. I always forget this. ;-)

non_active_record_model.rb

class NonActiveRecordModel
  include ActiveModel::Validations
  include ActiveModel::Conversion
  extend  ActiveModel::Naming

  def persisted?; false end

  def initialize(hash = {})
    hash.each do |key, value|
      m = "#{key}="
      self.send(m, value) if self.respond_to?(m)
    end
  end

end