Grunt

Hello there dear repository owner,

On this wonderful but icy day I, as discussed on the awesome `#amsterdamphp` channel on `IRC` network `Freenode`, hereby present you this Pull Request adding the desired `Grunt` functionality to the glorious new site you are building. The the current `Assetic Configuration` is left as it is as I never used.

If this is your first encounter with `Grunt` but sure to check out their [getting started guide](http://gruntjs.com/getting-started) and the `Grunt` section I've added to the `README`. Grunts `watch` command probably could replace the assetic watch. If you have any question please comment here and you'll find me with the same username on Twitter and the user group's IRC channel.

Sincerely,

WyriHaximus

P.S. And good day to you good Sir.