gistfile1.rb

# model name is "Code"  
# using acts_as_taggable

# takes in URL like domain.com/code/tags/first-tag+second-tag
# variable foo splits the string, sorts alphabetically, and rejoins the string
# if the current params don't equal the sorted params, redirect to
# code_tags_path plus the sorted string


# codes_controller.rb
def index
    @tags = Code.tag_counts_on(:tags).join(", ").split(", ").sort!

      if params[:tag]

        # sort tags param string alphabetically
        sorted_tags = params[:tag].split("/").sort_by!{ |m| m.downcase }.uniq.join("/")

          # redirect if out of order
          if params[:tag] != sorted_tags
            redirect_to code_tags_path+sorted_tags, status: 301
          else
            @codes = Code.tagged_with(params[:tag].split("/"))
          end

        @params = params[:tag].split("/")
        @tags = @tags-@params

      else
        @codes = Code.find(:all, :order => "updated_at DESC")
      end
  end


# routes.rb
get "/code/tags/:tag", to: "codes#index", as: :code_tag