add shujaaz ribbon to top right corner of homepage

Fixes #1572.

![screen shot 2014-11-26 at 15 09 36](https://cloud.githubusercontent.com/assets/739624/5203407/4aa21d1c-757e-11e4-9237-640bee537ec5.png)

The entire ribbon (and the triangular space below it, unfortunately) is clickable, and takes you to `/shujaaz` (which 404s on this branch, but I'm told it's right).