thanks for the tutorial.
When I was trying it out, the pages wouldn't load because of your bootstrap css and js. (//netdna.bootstrapcdn.com/bootstrap/3.0.0/css/bootstrap.min.css)
I don't know why it's causing that, as I can open the files in my browser just fine, but I had to comment them out of application.html.erb in order to run your example.
I just noticed this open issue. I will close it. I just downloaded the repo anew, installed everything and started to server. It downloaded the files just fine for me. If anyone else is having issues please open a new ticket.