Check if Registration exists

aleksis/apps/paweljong/models.py

@@ -50,6 +50,9 @@ class Event(ExtensibleModel):
             if request.user.person in self.linked_group.members.all():
                 return False
 
+            if EventRegistration.objects.filter(person=request.user.person).exists():
+                return False
+
             if (
                 Voucher.objects.filter(event=self, person=request.user.person, used=False).count()
                 > 0