readme: fix gruntJS getting start link

Author: Julien Bouquillon

README.md

@@ -12,7 +12,7 @@ npm install --save-dev grunt-filerev
 ```
 
 [grunt]: http://gruntjs.com
-[Getting Started]: https://github.com/gruntjs/grunt/blob/devel/docs/getting_started.md
+[Getting Started]: http://gruntjs.com/getting-started
 
 
 ## Overview