feat: add environment configuration.

#118

![screen shot 2014-12-03 at 11 41 54 am](https://cloud.githubusercontent.com/assets/2622152/5278404/aeec1242-7ae1-11e4-8692-79506508725f.png)
![screen shot 2014-12-03 at 11 41 27 am](https://cloud.githubusercontent.com/assets/2622152/5278403/aed88e20-7ae1-11e4-8626-885b6a2062a5.png)