Developers can be confident in deploying new, tested, code to the app

[gabestein]

Why

• We want to be able to build things quickly without worrying about releasing bad code
• This is particularly important if we want to support self-hosting, particularly pushing updates to the code for folks who are self-hosting
• We want to be confident that the app will scale to many thousands of pubs and users

Assumptions

• We should have much better test coverage across the app, including scalability/reliability and an understanding of what our test practices should be.
• Our deployment process to staging and dev should run those tests
• This work should probably include a basic feature flag system, in particular so we can launch actions to particular communities to test them without launching to all of them
• We need a migration, data migration, and rollback strategy as we're moving off prisma