Add language to highlight code syntax

* before
![2013-12-10 21 44 48](https://f.cloud.github.com/assets/290782/1714019/e6a0ea7c-6198-11e3-94f0-9671fdea5ccf.png)

* after
![2013-12-10 21 44 53](https://f.cloud.github.com/assets/290782/1714023/e937c49a-6198-11e3-9fbd-2a8d65108ae6.png)