class ActiveAdmin::Views::TableFor

def build_table_header(col)
  classes = Arbre::HTML::ClassList.new
  sort_key = sortable? && col.sortable? && col.sort_key
  params = request.query_parameters.except :page, :order, :commit, :format
  classes << "sortable" if sort_key
  classes << "sorted-#{current_sort[1]}" if sort_key && current_sort[0] == sort_key
  classes << col.html_class
  if sort_key
    th class: classes do
      link_to col.pretty_title, params: params, order: "#{sort_key}_#{order_for_sort_key(sort_key)}"
    end
  else
    th col.pretty_title, class: classes
  end
end