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app/models/bid.rb

@@ -29,6 +29,7 @@ class Bid < ActiveRecord::Base
   has_many :courses, :through => :homework_for_courses, :source => :project
   has_many :homeworks, :class_name => 'HomeworkAttach', :dependent => :destroy
   has_many :join_in_contests, :dependent => :destroy
+  has_many :praise_tread, as: :praise_tread_object, dependent: :destroy
   # has_many :fork_homework, :class_name => 'Bid', :conditions => "#{Bid.table_name}.parent_id = #{id}"
   
 

app/models/contest.rb

@@ -12,6 +12,7 @@ class Contest < ActiveRecord::Base
   has_many :acts, :class_name => 'Activity', :as => :act, :dependent => :destroy
   has_many :join_in_competitions, foreign_key: 'competition_id', :dependent => :destroy
   has_many :join_in_contests, class_name: 'JoinInCompetition', foreign_key: 'competition_id', :dependent => :destroy
+  has_many :praise_tread, as: :praise_tread_object, dependent: :destroy
 
   
 

app/models/issue.rb

@@ -46,6 +46,7 @@ class Issue < ActiveRecord::Base
   # added by fq
   has_many :acts, :class_name => 'Activity', :as => :act, :dependent => :destroy
   # end
+  has_many :praise_tread, as: :praise_tread_object, dependent: :destroy
 
 
   acts_as_nested_set :scope => 'root_id', :dependent => :destroy

app/models/praise_tread.rb

@@ -1,4 +1,6 @@
 class PraiseTread < ActiveRecord::Base
   attr_accessible :user_id,:praise_tread_object_id,:praise_tread_object_type,:praise_or_tread
+  belongs_to :user
+  belongs_to :praise_tread_object, polymorphic: true
  
 end