diff --git a/app/models/game.rb b/app/models/game.rb
index 144dbced2..d0d59c0e3 100644
--- a/app/models/game.rb
+++ b/app/models/game.rb
@@ -7,6 +7,7 @@
 class Game < ApplicationRecord
   default_scope { order("games.created_at desc") }
 
+  #TODO: games表要增加challenge_id与user_id的唯一索引
   has_many :outputs, -> { order('query_index DESC') }
   has_many :challenge_samples, :dependent => :destroy
   has_many :game_codes, :dependent => :destroy