Show error traces in production in Rails 3.1

I wanted to be able to see error traces in the browser when I'm the one visiting.

Here's my hack, dropped into config/initalizers/

if Rails.env == 'production'
  class ActionDispatch::Request
   def local?
     App.developer_ips.include?(remote_ip)
   end
  end
end

App.developer_ips is an array of IP addresses that I typically work from.