Updated Heroku deployment guide and add PATCH

[kathgironpe]

fixes sinatra/sinatra-book/#62
fixes sinatra/sinatra-book/#64

[zzak]

Seems good to me!

@kgrz want to review and merge?

Thanks for working on this! Historically this book was a guide for users wanting to know more about using Sinatra with other libraries and building little apps. Overtime this got to be too big and we decided to create the recipes project which is more of a cookbook style format. I had plans to work on this project and make it a more detailed guide for building an app from start to finish with Sinatra but haven't had time.

You're welcome to fix it up and do whatever you'd like with it, feel free to ask any questions or submit any patches, thanks!

[kathgironpe]

@zzak Recipes are good but most people like a book or documentation format. Having no book or documentation to read feels weird for most in fact. I saw very few free resources for Sinatra and Ruby in general. Thanks for working on this. I will try to contribute as much as I can.