Debian autotest setup

I spent some time learning Ruby on Rails these days and I had some trouble setting up autotest on my Debian box.
I finally managed to make it work thanks to these instructions.

$ sudo gem install ZenTest
$ sudo gem install autotest-rails
$ sudo apt-get install libnotify-bin
$ sudo gem install test_notifier

And then add require test_notifier/runner/autotest" to the file ~/.autotest