fix tests

The tests were not properly starting the quart app. This was an issue for at least #10 when writing tests.

Author: Cobalt

tests/test_gino_quart.py

@@ -33,6 +33,7 @@ async def _app(config):
     )
 
     db = Gino(app)
+    await app.startup()
 
     class User(db.Model):
         __tablename__ = "gino_users"