@starsirius  => Add an API playground.

Makes the app management page(s) prettier and adds an API playground using Swagger.

![screenshot 2014-08-27 11 58 04](https://cloud.githubusercontent.com/assets/542335/4062835/f5b81c4c-2e02-11e4-9d9a-d830ab65c374.png)

Bootstrap has an [alert](http://getbootstrap.com/components/#alerts) component which is easy to start. We actually have a [customized flash message](http://partner-engineering-style-guide.s3-website-us-east-1.amazonaws.com/elements/flash_messages/) in [Watt](https://github.com/artsy/watt) if we plan to use it (it might change in the future tho, given that we are continuously updating the UIs.)