Readd setting up groups with comma seperated list

homeassistant/components/group.py

@@ -103,6 +103,8 @@ def get_entity_ids(hass, entity_id, domain_filter=None):
 def setup(hass, config):
     """ Sets up all groups found definded in the configuration. """
     for name, entity_ids in config.get(DOMAIN, {}).items():
+        if isinstance(entity_ids, str):
+            entity_ids = entity_ids.split(",")
         setup_group(hass, name, entity_ids)
 
     return True