Tags no son necesarias al agregar una entidad a la lista

lists/models.py

@@ -31,7 +31,7 @@ class ListItem(Model):
     """Item de la lista de un usuario"""
     user = ForeignKey(User, on_delete=CASCADE, related_name='list')
     entity = ForeignKey(Entity, on_delete=CASCADE)
-    tags = ManyToManyField(Tag, related_name='list')
+    tags = ManyToManyField(Tag, related_name='list', blank=True)
 
 
 class Stars(Model):

lists/test.py

@@ -87,6 +87,29 @@ class TestList(TestCase):
         self.assertEqual(list_item.entity_id, to_add['entity'])
         self.assertEqual(list_item.tags.count(), len(to_add['tags']))
 
+    def test_add_to_list_no_tags(self):
+        to_add = {
+            'entity': 'b',
+            'entity_type': 'artist',
+            'tags': []
+        }
+
+        response = self.client.post('/api/lists/list/1/', json.dumps(to_add),
+                                    content_type='application/json',
+                                    HTTP_AUTHORIZATION=self._user_bearer_token())
+
+        self.assertEqual(response.status_code, 200)
+
+        list_item = ListItem.objects.filter(pk=2)
+
+        self.assertEqual(list_item.count(), 1)
+
+        list_item = list_item[0]
+
+        self.assertEqual(list_item.user_id, self.user.id)
+        self.assertEqual(list_item.entity_id, to_add['entity'])
+        self.assertEqual(list_item.tags.count(), len(to_add['tags']))
+
     def test_add_to_list_non_exists_entity(self):
         to_add = {
             'entity': 'd',