Rinku is a drop-in replacement for Rails 3.1 auto_link.
Auto-linking functionality has been removed from Rails 3.1, and is instead offered as a standalone gem, rails_autolink. You can choose to use Rinku instead.
require 'rails_rinku'
The rails_rinku package monkeypatches Rails with an auto_link method that mimics 100% the original one, parameter per parameter. It’s just faster.