feat: add group management for workers and shifts, including validation for overlapping groups

djangorota/rota/models.py

@@ -274,6 +274,17 @@ class Worker(models.Model):
 					else:
 						pyd_kwargs[k] = []
 
+				set_keys = ["groups"]
+				for k in set_keys:
+					v = pyd_kwargs.get(k, None)
+					try:
+						if v is None:
+							pyd_kwargs[k] = set()
+						else:
+							pyd_kwargs[k] = set(v)
+					except Exception:
+						pyd_kwargs[k] = set()
+
 				# allowed_multi_shift_sets is expected to be a list of sets; if the
 				# DB contains lists-of-lists convert inner lists to sets.
 				ams = pyd_kwargs.get("allowed_multi_shift_sets")