"Building the build" documentation (development documentation)

[froboy]

@becw I realized I'm not totally sure what the best way to work on the build is. Most of the time I think I've done some git acrobatics on an existing project, but if there was some documentation on how best to contribute to the project, that'd be awesome.

Potential topics:

• Getting a test project up and running with the build
• Working on the build in an existing project
• Potential pitfalls
• Common scenarios to test for

Thanks!