Add deploy-to-tsuru script, README tweaks

This adds a shell script called `deploy-to-tsuru`, that uh, deploys to tsuru.

And then I reference it in `README.md` and made a few other tweaks.

Here's what the output of `deploy-to-tsuru` looks like: https://gist.github.com/msabramo/164f1bdbbd3c56d59df6
That's a good idea. I actually wrote 2 plugins the other day:

- https://github.com/msabramo/tsuru_plugin_app-url
- https://github.com/msabramo/tsuru_plugin_app-git-remote

This could be a useful plugin too. Thanks for the idea!