Upgrading to rails3 - request_routing plugin issue

We are working on upgrade some application from rails 2.3.4 to rails 3.0.4 and we want to share with you some thoughts and solutions.

The first solution we want to show you is particulary useful if you are working on app you didn't create or you did it years ago and you have no idea why ;)

If you see error similar to that when you are running your app:

.rvm/gems/ruby-1.8.7-p334/gems/actionpack-3.0.4/lib/action_dispatch/routing/route_set.rb:298:in `initialize': wrong number of arguments (7 for 2) (ArgumentError)

that means your app has installed request_routing plugin. Is there version for rails3? Probably not, but solution is simple! You don't need this plugin in rails3 so you can just remove it to solve this problem.