去掉新手10回复发帖限制
优化 /notifications;
Merge branch 'master' of github.com:ruby-china/ruby-china
个人主页首页的帖子按照受欢迎度排序;
会员栏目改为 Top 100 活跃会员，去掉新注册会员的罗列；
个人主页受欢迎的帖子列表排除掉某些节点.
Reproduce #173 using rspec.
Replace user placeholder in code after markdown.
Merge pull request #174 from doitian/bug/173-user-placeholder-in-coffee

Bug/173 user placeholder in coffee
Merge pull request #2 from ruby-china/master

合并原作者的更新