Fix syntax highlight in blog post

`hbs` is not valid language name.

Before:
![2014-11-06 2 12 28](https://cloud.githubusercontent.com/assets/290782/4922078/22405034-650f-11e4-8504-4a045b636f4c.png)

After:
![2014-11-06 2 12 37](https://cloud.githubusercontent.com/assets/290782/4922079/25820e4a-650f-11e4-8437-737687d595ba.png)