Add documentation

[Goff-Davis]

Architecture Documentation

An ARCHITECTURE.md file should be created. See here for a somewhat preachy explanation of what that is.

It should cover:

• the database design (what are the different table, what purpose do they serve, overall design)
• Each of the endpoints, what input they expect and what output they give, the files associated with them
• Anything else you think would help give someone an effective mental map of the backend

Readme

Make sure the readme is up to date with all the latest environment variables, commands, and explanations on how to get started developing and deploying.

Commenting

Comments should be added to code that is complex or could be hard to understand. Don't do line by line or real nitty gritty stuff since that can change, but explain the reasoning behind a section, for example.