refactor for better plugin integration

lib/cmtool/engine.rb

@@ -16,6 +16,9 @@ module Cmtool
     isolate_namespace Cmtool
     initializer "cmtool.build_menu" do
       require 'email_validator'
+      require 'bourbon'
+      require 'slim-rails'
+      require 'haml-rails'
       Cmtool::Menu.register do
         group label: :site do
           title t('cmtool.menu.site.title')

lib/cmtool/menu.rb

@@ -169,12 +169,12 @@ module Cmtool
         @items = @before + @items + @after
       end
 
-      def append_to(label, &block)
+      def append_to(label, options = {}, &block)
         item = items.find{|i| i.options[:label] == label}
         if item
           register = item.instance_variable_get('@register')
           if register
-            register.instance_variable_get('@items') << Cmtool::Menu::Divider.new
+            register.instance_variable_get('@items') << Cmtool::Menu::Divider.new unless options[:skip_divider].present?
             register.instance_eval(&block)
           end
         else