Write the really awesome documentation (guacamolegem.org)

* [x] Buy and configure guacamolegem.org
* ~~Create a layout like [Zepto](http://zeptojs.com)'s~~
* [x] Write an overview for the concept of Guacamole (What is a Model? What is a Collection?)
* [x] Give a walkthrough through all functionality with pointers to other resources (Virtus doc for example)
* [x] Provide advice about popular third party gems like Fabricator, authentication gems etc.