module ActiveAdmin
  module Reorderable
    module TableMethods

      def reorder_column
        column '', :class => 'reorder-handle-col' do |resource|
          reorder_handle_for(resource)
        end
      end

      private

      def reorder_handle_for(resource)
        url = [active_admin_config.route_instance_path(resource), :reorder].join('/')
        span(reorder_handle_content, :class => 'reorder-handle', 'data-reorder-url' => url)
      end

      def reorder_handle_content
        '&equiv;&equiv;'.html_safe
      end

    end

    ::ActiveAdmin::Views::TableFor.send(:include, TableMethods)
  end
end


module ActiveAdmin
  module Reorderable
    module TableMethods

      def reorder_column
        column '', :class => 'reorder-handle-col' do |resource|
          reorder_handle_for(resource)
        end
      end

      private

      def reorder_handle_for(resource)
        url = url_for([:reorder, active_admin_namespace.name, resource])
        span(reorder_handle_content, :class => 'reorder-handle', 'data-reorder-url' => url)
      end

      def reorder_handle_content
        '&equiv;&equiv;'.html_safe
      end

    end

    ::ActiveAdmin::Views::TableFor.send(:include, TableMethods)
  end
end


--- 
+++ 
@@ -11,7 +11,7 @@
       private
 
       def reorder_handle_for(resource)
-        url = url_for([:reorder, active_admin_namespace.name, resource])
+        url = [active_admin_config.route_instance_path(resource), :reorder].join('/')
         span(reorder_handle_content, :class => 'reorder-handle', 'data-reorder-url' => url)
       end
 
Fix URL builder for reorder route

Preference is to use ActiveAdmin's built-in route builder so we get the
correct namespace and model naming.
