I made a very basic applescript app that registers the rubymine:// url scheme.
Make sure you use the Rubymine Beta 5 or higher.
Update your rubymine command-line-launcher by going to Tools -> Create Command-line Launcher
The full url should be in the form of : rubymine://open?url=file://FULL_LOCAL_PATH_TO_FILE&line=LINE_NUMBER
I would advice to use BetterErrors (which kicks ass !) available here : https://github.com/charliesome/better_errors
Just put gem "better_errors" in your Gemfile
Then in your development.rb puts
You should now be able to click the error urls and rubymine will jump to it for you :)
RubyMine Url Handler.zip