SecureDrop Client ERD

[Er1kkkaaa]

Description

The following displays an ER diagram for the SecureDrop-Client database. It was created using the MySQL Workbench. @eloquence @creviera Please let me know if there is anything else that I can add to / needs to be changed. 😄
If everything looks fine, I will share the .mwb file as well!

Fixes #1146

[sssoleileraaa]

I think we can remove the alembic_version box and then this lgtm! https://docs.securedrop.org/en/stable/development/client.html would be a good location for this diagram where you can add a section similar to what we have for the server database: https://docs.securedrop.org/en/stable/development/tips_and_tricks.html#architecture-diagrams.

We manage our docs in a separate repo called securedrop-docs. Here's how you can get started with making a docs PR: https://github.com/freedomofpress/securedrop-docs#quickstart

[sssoleileraaa]

This is closed by freedomofpress/securedrop-docs#271