Development playground from the treehouse course (that I keep updating for exercise).
Ruby 2.0.0p247
Rails 4.1.0
###On Heroku###
Also available on Heroku: http://fathomless-anchorage-4126.herokuapp.com/
Of course trying to use the methods that send emails won't work in Heroku (at least for now, it ask for my credit card to use a free of charge addon)
pro-tip: to deploy on Heroku it is best to always use the most recent version of ruby and rails.