Update README.md

Update test comments.

README.md

@@ -2,7 +2,7 @@
 
 This library is based on django’s mysql backend and change some logic and support features to fit TiDB.
 
-For now this package is tested in python 2.7
+For now this package is tested in python 2.7 and django 1.8.x
 
 # Usage