course revert search project

app/models/course.rb

@@ -2,7 +2,7 @@ class Course < ActiveRecord::Base
   include Redmine::SafeAttributes
   
   attr_accessible :code, :extra, :name, :state, :tea_id, :time , :location, :state, :term, :password
-  belongs_to :project, :class_name => 'Project', :foreign_key => :extra # 定义一个project方法， 该方法通过extra来调用project表
+  belongs_to :project, :class_name => 'Project', :foreign_key => :extra, primary_key: :identifier
   belongs_to :teacher, :class_name => 'User', :foreign_key => :tea_id  # 定义一个方法teacher，该方法通过tea_id来调用User表
   belongs_to :school, :class_name => 'School', :foreign_key => :school_id #定义一个方法school，该方法通过school_id来调用School表
   has_many :bid

app/models/user.rb

@@ -18,6 +18,11 @@
 require "digest/sha1"
 
 class User < Principal
+  TEACHER = 0
+  STUDENT = 1
+  ENTERPRISE = 2
+  DEVELOPER = 3
+  
   include Redmine::SafeAttributes
 
   # Different ways of displaying/sorting users