Wiki DNS Changes break Rails Scripts

Moving the Rails wiki to the new wiki breaks several places where Rails points to wiki URLs:

railties/rails/lib/rails_generator/scripts.rb, Rails::Generator::Scripts::Base#usage_message points to http://wiki.rubyonrails.org/rail...

railties/rails/lib/commands/plugin.rb, Discover#parse! and Discover#scrape both try to use the wiki to get the list of Rails plugins.

The basic problem is that none of those pages have been ported to the new wiki. Not sure the best fix: the old wiki was pretty much a mess on both those pages, but people still seem to depend on them judging by IRC feedback. But it seems like we either need to fix the code to not point people there any more (breaking compat with existing Rails installs), or copy the pages over to the new wiki. If you like the "copy pages" solution, feel free to assign back to me - I can work with the wiki team to make sure this happens.