Issue 1: Project pivot加上created_by_user_id modified_by_user_id字段
Status:  Assigned
Owner:
Project Member Reported by com...@gmail.com, Aug 8, 2008
做法
1 修改数据库结构,在相关的model数据表中增加两个字段
  created_by_user_id
  modified_by_user_id
2 在application.rb中
 user_stamps Material,Segment,Item
 ==>
  user_stamps Material,Segment,Item ,Project,Pivot