删除项目，竞赛表project_id会置空，projecting_softapplications模型不知道干嘛用，此表也不存在

app/models/softapplication.rb

@@ -10,7 +10,6 @@ class Softapplication < ActiveRecord::Base
   belongs_to :user
   belongs_to :project
   has_many :contests, :through => :contesting_softapplications
-  belongs_to :project
 
   def add_jour(user, notes, reference_user_id = 0, options = {})
     if options.count == 0