You can clone with
HTTPS or Subversion.
I'm on 14.04 Trusty Gnome Ubuntu, but I believe that this may be a problem on other distros. I think you need to add a lines for:
sudo aptitude install libsqlite3-dev
sudo aptitude install nodejs
before you can run rails. Also the "--no-document" commands don't work for some of the installs.
Fixed in the aforementioned PR.