This is a good thing to do if your site relies on either a solid SEO strategy, OR if you use page caching which will consider the order of the params for its cache keys.
This works for Rails 3.2+
Older version of Rails will need to replace
request#original_url with some other way to get the current full URL.
class ApplicationController < ActionController::Base
# url_for(params) in later version of Rails will sort the params.
sorted_url = url_for(params)
# request#original_url is only available in Rails 3.2+
redirect_to sorted_url if request.original_url != sorted_url