Collaborative Coding Chapter

[cdsupina]

We need a section on collaborative coding with Git/Github. At the end of the simple gun weapon section I mentioned making PR. We should write a chapter on collaborative coding (PR, Issues, Code Review, etc), so that Fish Fight can be a welcoming entry point for newer programmers.

We should feel free to reference external resources for the fundamentals, but we should specify the conventions and etiquette that may be more specific to Fish Fight.

This Theta Wave Legacy book page may be a good reference: https://github.com/thetawavegame/thetawave-legacy/blob/master/book/src/contributing.md