Firefox 19 and unable to obtain stable firefox connection in 60 seconds

Problem
You have just upgraded your Firefox to the latest release (currently 19) and when running your javascript cucumber tests you get the following error:

 unable to obtain stable firefox connection in 60 seconds

Solution
Add the latest selenium-webdriver to your Gemfile and run bundle update:

gem "selenium-webdriver", "~> 2.30.0", :group => :test