US12: Documentation For App (Wiki doc)

[Obarrie]

Developer Documentation. As a team, add a wiki to your repo where you document
anything future developers need to know to modify your app (front ends and backend).
Your wiki must contain an overview of your product, and documentation on how it works.
The documentation must contain at least:

• A full-stack diagram showing interactions among front end(s), backend
  (including at least authentication and database, and cloud functions (if
  any)), and any external web APIs that the app uses;
• The database schema;
• Screenshots of app screens and their supporting blocks. Complex blocks
  are to have their own screenshot and subsection explaining them in
  detail.
• Subsections on each cloud function showing its code and explaining it.
• Whatever else a developer would need to contribute to your app.
  Use the wikis shown in the Week 10 material (including their linked subpages) as
  examples.