Sorting by association using the "as action" attribute

I'm trying to dynamically sort the table Posts

by means of :type

using Acts-as with the on-taggable- gem.

Let's say my Post object has 3 columns: user, title and date. I can easily sort the Post table by inserting my controller@entries = Post.order(sort_column + " " + sort_direction).page(params[:page])

sort_column

and sort_direction

are referred to as:

def sort_column
  Post.column_names.include?(params[:sort]) ? params[:sort] : "published_at"
end

def sort_direction
  %w[asc desc].include?(params[:direction]) ? params[:direction] : "desc"
end

      

        
        
        
      

    

However, Post can also have a type attached to it . In my Post model, I have:

acts_as_taggable
acts_as_taggable_on :types 

      

        
        
        
      

    

and in my view table I just show the tag, write:

views / posts / _posts.html.slim

...
td.tags = entry.type_list.first.titleize unless entry.type_list.blank?
...

      

        
        
        
      

    

Is there an easy way to alphabetically sort a table by type ?