Features: 1) Use AbstractGateway for processing transactions in signals;

Fixes: 1) Add missing import for `AbstractGateway` in `signals.py`;

Extra: n/a;

payments/signals.py

@@ -1,6 +1,7 @@
 from django.db.models.signals import post_save
 from django.dispatch import receiver
 
+from payments.gateways import AbstractGateway
 from payments.models import Balance, Transaction
 from payments.utils.emailing import balance_deposit_email
 from vibes_auth.models import User
@@ -16,7 +17,7 @@ def create_balance_on_user_creation_signal(instance, created, **_kwargs):
 def process_transaction_changes(instance, created, **_kwargs):
     if created:
         try:
-            gateway = object()
+            gateway = AbstractGateway()
             gateway.process_transaction(instance)
         except Exception as e:  # noqa:
             instance.process = {"status": "NOGATEWAY", "error": str(e)}