Changed Readed

While I'm at it: I reorganised the Readme a bit.
It was quite confusing to me at first, so I tried an improved how everything was layed out.

I also removed references to bamboo since the command given to create the app on Heroku ask for the new Cedar stack.

If you want to see how it looks:
https://github.com/marcgg/huboard/tree/rewrite-readme