I did manage to install it with ‘install railroad gem’, problem is that when I run any command like ‘railroad -a -i -M | dot -Tpng > doc/models.png’ it doesn’t work, I get this:
from /Users/rodrigoruiz/.rvm/gems/ruby-1.9.2-p180@rails3/gems/railroad-0.5.0/lib/railroad/app_diagram.rb:72:in `load_environment'
from /Users/rodrigoruiz/.rvm/gems/ruby-1.9.2-p180@rails3/gems/railroad-0.5.0/lib/railroad/app_diagram.rb:18:in `initialize'
from /Users/rodrigoruiz/.rvm/gems/ruby-1.9.2-p180@rails3/gems/railroad-0.5.0/lib/railroad/models_diagram.rb:14:in `initialize'
from /Users/rodrigoruiz/.rvm/gems/ruby-1.9.2-p180@rails3/gems/railroad-0.5.0/bin/railroad:36:in `new'
from /Users/rodrigoruiz/.rvm/gems/ruby-1.9.2-p180@rails3/gems/railroad-0.5.0/bin/railroad:36:in `<top (required)>'
from /Users/rodrigoruiz/.rvm/gems/ruby-1.9.2-p180@rails3/bin/railroad:19:in `load'
from /Users/rodrigoruiz/.rvm/gems/ruby-1.9.2-p180@rails3/bin/railroad:19:in `<main>'