Add link to angularjs patterns: clean code course @ pluralsight

Used same link as in readme.md from the [angularjs-styleguide](https://github.com/johnpapa/angularjs-styleguide/blob/master/README.md):
http://jpapa.me/ngclean 
```--> redirects --> ```
http://www.pluralsight.com/courses/angularjs-patterns-clean-code