Fix some bug and add user admin
Merge pull request #229 from liuchuangww/user

Fix some bug and add user admin
User module in process
Merge pull request #230 from liuchuangww/user

User module in process
Merge pull request #231 from linzongshu/user

Achieved image upload
Refactoring message module
Refactoring message module
Code cleaning up
Added placeholder for QQ avatar
Typo fix
User module in process
Merge pull request #232 from sexnothing/user

User module in process
Added source hash for upload avatar
User module in process
Merge pull request #233 from liuchuangww/user

User module in process
User module in process
Merge pull request #234 from liuchuangww/user

User module in process
User module front-end in process
Merge pull request #235 from sexnothing/user

User module front-end in process
Added create/add APIs to Pi::db()->where()  for predicates