[Radiant] How to add a before_filter?

[Chris Perkins]

I'm redoing an existing website, and there is one thing I can't figure out 
how to do. I want to redirect some funky URLs that that the old website 
uses to the new, simpler ones that radiant uses.

In a vanilla Rails app, I would add a before_filter in my 
ApplicationController, something like this;

class ApplicationController < ActionController::Base
  before_filter :redirect_old_urls
  def redirect_old_urls
    if is_funky(request.fullpath)
      redirect get_new_url(require.fullpath)
    end
  end
end

Something like that, anyway.

But my radiant app doesn't have an application_controller.rb, so I don't 
know where to put this.  Any suggestions?

- Chris