Merge pull request #180 from taiwen/user

User model bug fixes
Merge pull request #181 from taiwen/user

Added APIs for timeline/activity/log
Merge pull request #182 from taiwen/user

Added APIs for timeline/activity/log
Merge pull request #183 from taiwen/user

Added APIs for timeline/activity/log
Merge pull request #184 from taiwen/user

Implemented user data
User module in process
Merge pull request #185 from liuchuangww/user

User module in process
Implemented user data APIs