Deploy a "dev" instance that has an in-memory database for deploy previews

[thomaseizinger]

Starting with nobt-io/frontend#301, we use netlify and have deploy previews for each branch.

It would be good to have a dev version of the API sitting at dev-api.nobt.io which only uses an in-memory database.

This API could then be used to test deploy previews without polluting the production database too much.