Great work. But if I may add a point for improvement:

In your main file, I see that you have DB-creds hardcoded:

container.config.from_dict( dict( # DATABASE_URL="sqlite+pysqlite:///:memory:", DATABASE_URL="postgresql://postgres:password@localhost:5432/postgres", DATABASE_ECHO=False, DEBUG=True, ) )

From a security-perspective, this would be problematic.