Sort the tag of jekyll in Posts.

tag_order.rb

module Jekyll
  module Filters
    def tag_order(tags, order, orderby='ASC')

      # order
      case order
      when 'count' then
        order_tags = tags.sort_by { | t, posts | posts.count }
      end

      # orderby
      case orderby
      when 'ASC' then
        orderby_tags = order_tags
      when 'DESC' then
        orderby_tags = order_tags.reverse
      end

      return orderby_tags
    end
  end
end