Add Alembic to project for database migrations

tofu_api/app.py

@@ -60,12 +60,8 @@ class App(Flask):
         # Import models to fill the metadata object
         import tofu_api.models  # noqa (unused import)
 
-        # Create all tables
-        # TODO: Use migrations instead
-        db.create_all_tables()
 
-
-def create_app() -> Flask:
+def create_app() -> App:
     """
     App factory, returns a Flask app object.
     """