Cloning this repository:

git clone git://gitorious.org/emacs-rails/emacs-rails.git emacs-rails
cd emacs-rails

Add this repository as a remote to an existing local repository:

git remote add emacs-rails git://gitorious.org/emacs-rails/emacs-rails.git
git fetch emacs-rails
git checkout -b my-local-tracking-branch emacs-rails/master_or_other_branch