Documentation: Windows users use a VM

I enjoy working with middleman. However after my first projects I have come to the conclusion that working with middleman on Windows machines is guarantee for constant source of frustration. It seems to me there are so many extra steps to take to get things up and running and so many little pieces that don't quite work as they should (e.g. js compression or additional gems that have never been tested with Windows before) that most Windows users are just better off developing inside a Linux VM. It seems to me Windows is just not very well supported in the Ruby universe since not a lot of people use it. 

If you agree here is a patch.