UESTC-ACM/CDOJ — pull request #149 by mzry1992 (2014-03-21 14:36:45+00:00)
Title: Simple comment system and contest clarification

User can comment / reply comment like renren.

Show unread clarification number.

![qq20140321-6](https://f.cloud.github.com/assets/2420472/2483872/2e147510-b106-11e3-8bf1-190a7b9b70a1.png)