Their tutorial section covers it here but for the sake of dry-ness use this. It contains mephisto 0.73 with the proper rails version frozen in it and all the annoying details figured out (shebangs, htaccess etc) for working with HostingRails fastCGI setup.
Upload, unrar, update database.yml, rake, symlink, restart.
Notice for some reason rake db:bootstrap crashes so you gotta run the tasks manually.
rake db:schema:load RAILS_ENV=production
rake db:bootstrap:load RAILS_ENV=production
rake tmp:create
