add myself to contributors.md

contributors.md

@@ -69,4 +69,4 @@ Thank you to all contributors:
 * [Johan Manuel](https://github.com/29jm)
 * [Brian Rak](https://github.com/brakthehack)
 * [Robin Peiremans](https://github.com/rpeiremans)
-
+* [xiaoqiang zhao](https://github.com/hitmoon)