trustieforge/app/models/join_in_competition.rb

# 新竞赛参加关系表
class JoinInCompetition < ActiveRecord::Base
  attr_accessible :competition_id, :user_id
  belongs_to :user, :class_name => "User", :foreign_key => :user_id
  belongs_to :competition, :class_name => "Contest", :foreign_key => :competition_id

  validates :user_id, presence: true
  validates :competition_id, presence: true

end