added gtip CLI link

Author: nirajpandkar

README.md

@@ -3,6 +3,8 @@
 
 [English](http://git.io/git-tips) | [中文](https://github.com/521xueweihan/git-tips)
 
+[gtip](https://github.com/nirajpandkar/gtip) - A handy CLI to make optimum use of these tips.
+
 P.S: All these commands are tested on `git version 2.7.4 (Apple Git-66)`.
 
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