Make notification rule ID field UUID and fix default sources

core/models.py

@@ -1,4 +1,5 @@
 import logging
+import uuid
 
 import stripe
 from django.conf import settings
@@ -175,6 +176,9 @@ class Perms(models.Model):
 
 
 class NotificationRule(models.Model):
+    id = models.UUIDField(
+        default=uuid.uuid4, primary_key=True, editable=False, unique=True
+    )
     user = models.ForeignKey(User, on_delete=models.CASCADE)
     name = models.CharField(max_length=255)
     priority = models.IntegerField(choices=PRIORITY_CHOICES, default=1)