Better promotion on facebook

I noticed that when I shared this URL on Facebook that I didn't get an image preview:

![2014-11-15 20_56_01](https://cloud.githubusercontent.com/assets/121322/5060437/b9d692d0-6d09-11e4-8afa-16b7555bd06a.gif)

If you merge this pull request and use Facebook's [Open Graph Object Debugger](https://developers.facebook.com/tools/debug/og/object/) to rescrape the site then you should start seeing this instead:

![screen shot 2014-11-15 at 9 00 20 pm](https://cloud.githubusercontent.com/assets/121322/5060443/30879d0c-6d0a-11e4-81ba-86465c9d2a03.png)

Studies have shown that will drive engagement, likes, shares, people playing, etc :chart_with_upwards_trend: 

Cheers,
  Lee :beers:

/cc @mrtnkl