Example of using also_validates for racquet.io

match_entry.rb

class MatchEntry
  include Informal::Model

  attr_accessor :winner_registration, :loser_registration
  validate :different_twitter_handles?
  also_validates :winner_registration, :loser_registration

  def initialize(options = {})
    @winner_registration            = options[:winner_registration]
    @loser_registration             = options[:loser_registration]
    @club                           = options[:club]
  end

  def save_match
    return false unless valid?
    @club.matches.create(winner: @winner_registration.member, loser: @loser_registration.member)
  end

  private

  def different_twitter_handles?
    if @winner_registration.twitter_handle == @loser_registration.twitter_handle
      errors.add(:base, "Winner and loser must be different players")
    end
  end

end