JS for generating blog subdomain

Just something neat to have on the new blog form. Where it takes text from the blog name and parses it properly for permalinks. E.g. "hello world 123" -> "hello-world-123".
Not a massive fan of having the coffeescript in the blog form.html.haml but it will only be generated on that form in this instance.
This is something from one of my blogging apps that I still haven't got round to launching properly yet!
I've also added .rvmrc & .powrc to the .gitignore otherwise these may be committed by me by accident.