The gem is based on Rick Olson's code of ActiveModel::StateMachine, axed from ActiveModel in this commit.
Currently there's no gem released on gemcutter (we need a different name). However it's fully usable in bundler, you can just paste the following line into the Gemfile:
gem "state_machine", :git => "git://github.com/qoobaa/state_machine.git"
Fork the project.
Make your feature addition or bug fix.
Add tests for it. This is important so I don't break it in a future version unintentionally.
Commit, do not mess with rakefile, version, or history. (if you want to have your own version, that is fine but bump version in a commit by itself I can ignore when I pull)
Send me a pull request. Bonus points for topic branches.
Copyright © 2010 Jakub Kuźma. See LICENSE for details.