add installation instructions to homepage

:bee: WIP :bee: WIP :bee: WIP :bee: WIP :bee: WIP :bee: WIP :bee: WIP :bee:

![screen shot 2014-11-13 at 11 08 09 pm](https://cloud.githubusercontent.com/assets/2289/5042454/1a6a22f0-6b8a-11e4-91e9-6f311a4f8742.png)

:bee: WIP :bee: WIP :bee: WIP :bee: WIP :bee: WIP :bee: WIP :bee: WIP :bee: