add: add login api

core/apps/orders/signals/__init__.py

@@ -0,0 +1 @@
+from .order import *

core/apps/orders/signals/order.py

@@ -0,0 +1,12 @@
+from django.db.models.signals import post_save
+from django.dispatch import receiver
+
+from core.apps.orders.models import Order
+
+
+@receiver(post_save, sender=Order)
+def set_order_number(sender, instance, created, **kwargs):
+    if created:
+        last_order = Order.objects.order_by('order_number').last()
+        instance.order_number = (last_order.order_number + 1) if last_order else 1
+        instance.save(update_fields=["order_number"])