Merge pull request #3 from blacktear23/issue2

#2 fix tidb not support save point

django_tidb/tidb/features.py

@@ -3,3 +3,4 @@ from django.db.backends.mysql import base as mybase
 
 class DatabaseFeatures(mybase.DatabaseFeatures):
     supports_foreign_keys = False
+    uses_savepoints = False