add milestone model
fix_bug: Unknow ualidator 'invalidator'
fix_bug: Unknow ualidator 'invalidator'
doing 'projects'
加入中文错误提示信息
加入flash提示框样式
Merge branch 'develop' into feature/UI_develop

* develop:
  加入flash提示框样式
  doing 'projects'
  fix_bug: Unknow ualidator 'invalidator'

Conflicts:
	app/models/project.rb
fix_bug: 'users#new' 页面返回 500
fix_bug: 'users#new' 页面返回 500
修改layout页面
修改创建用户页面
project页面加入基本样式
Merge branch 'develop' into feature/UI_develop

* develop:
  project页面加入基本样式
  修改layout页面
  fix_bug: 'users#new' 页面返回 500

Conflicts:
	app/views/users/_form.html.erb
外键加入非空，修改projects_list
fix_bug: 顶部导航栏显示
修改projects页面成3列
修改projects页面成3列
Merge pull request #8 from Scott1743/develop

Develop