Allow to pass user data to the widget (#1095)

- [x] Logic
- [x] Tests
- [x] Docs
- [x] find a way to integrate with tracking

src/pretix/base/models/items.py

@@ -750,7 +750,7 @@ class Question(LoggedModel):
 
     @staticmethod
     def _clean_identifier(event, code, instance=None):
-        qs = Question.objects.filter(event=event, identifier=code)
+        qs = Question.objects.filter(event=event, identifier__iexact=code)
         if instance:
             qs = qs.exclude(pk=instance.pk)
         if qs.exists():