Update README.md

Author: erickpintor

README.md

@@ -4,7 +4,7 @@ Plugin that highlights when you press tmux prefix key. Inspired by
 [this](http://stackoverflow.com/questions/12003726/give-a-hint-when-press-prefix-key-in-tmux)
 thread on stackoverflow.
 
-Many thanks to @obxhdx for showing me this trick.
+Many thanks to [@obxhdx](https://github.com/obxhdx) for showing me this trick.
 
 Prefix off:
 ![prefix_off](screenshots/prefix_off.png)