API: Allow to set order of check-in lists

doc/api/resources/checkinlists.rst

@@ -98,6 +98,8 @@ Endpoints
    :query string ends_after: Exclude all check-in lists attached to a sub-event that is already in the past at the given time.
    :query string expand: Expand a field into a full object. Currently only ``subevent`` is supported. Can be passed multiple times.
    :query string exclude: Exclude a field from the output, e.g. ``checkin_count``. Can be used as a performance optimization. Can be passed multiple times.
+   :query string ordering: Manually set the ordering of results. Valid fields to be used are ``id``, ``name``, and ``subevent__date_from``,
+                           Default: ``subevent__date_from,name``
    :param organizer: The ``slug`` field of the organizer to fetch
    :param event: The ``slug`` field of the event to fetch
    :statuscode 200: no error

src/pretix/api/views/checkin.py

@@ -93,8 +93,10 @@ with scopes_disabled():
 class CheckinListViewSet(viewsets.ModelViewSet):
     serializer_class = CheckinListSerializer
     queryset = CheckinList.objects.none()
-    filter_backends = (DjangoFilterBackend,)
+    filter_backends = (DjangoFilterBackend, RichOrderingFilter)
     filterset_class = CheckinListFilter
+    ordering = ('subevent__date_from', 'name')
+    ordering_fields = ('subevent__date_from', 'id', 'name',)
 
     def _get_permission_name(self, request):
         if request.path.endswith('/failed_checkins/'):