add menu_item model
menu_items admin CRUD
show menu_items hierarchically
delet page uri field
move admin pages controller in menu_items namespace
Merge branch 'develop' of github.com:kaize/castle into feature/menu-104

Conflicts:
	app/controllers/web/page_controller.rb
	app/models/page.rb
add show menu_items in navigation
add nav for pages
add locales for menu_items
add sorting pages with errors
fixes sortable for pages
Merge branch 'feature/menu-104' into staging

Conflicts:
	Gemfile.lock
	app/views/layouts/web/admin/shared/_navbar.html.haml
	app/views/web/admin/menu_items/pages/_form.html.haml
	db/schema.rb