Add Backend And Frontend Developer Mode and Documentation for Docker

[billyb2]

Depending on whether you're developing on the backend or not, you may want different features in your docker-compose then if you're just using the backend as a quick test. For instance, persistence of data is extremely useful if you're working on integrating game servers, steam, and login servers, but not so useful if you just want to make sure you can request data from the backend (or it could be, who knows!)

Since Docker doesn't really have modes, it'd likely just be commenting and uncommenting different features that you want.