Update billing.py

Author: beacoder

app/routes/billing.py

@@ -9,8 +9,8 @@
 from sqlalchemy.orm import Session
 
 from ..controllers import usage
+from ..infra.db import get_db
 from ..models import User
-from ..models.db import get_db
 from ..routes.auth import authenticate_user
 from ..validation.schemas import UsageSummary