Fix controller generator about cart controller

lib/generators/shotengai/controllers_generator.rb

@@ -49,7 +49,7 @@ module Shotengai
           'orders' => @order,
           'product_series' => "#{@product}Series",
           'product_snapshots' => "#{@product}Snapshot",
-          'carts' => 'Order::Cart',
+          'carts' => '::Order::Cart',
           
         }.each do |key, klass_name|
           @key, @klass_name = key, klass_name

lib/generators/templates/controllers/template_controller.rb

-class <%= @controller_prefix %><%= @klass_name.pluralize %>Controller < Shotengai::Controller::<%= "#{@role}/#{@key}".camelize %>Controller
+class <%= @controller_prefix %><%= @key.classify.pluralize %>Controller < Shotengai::Controller::<%= "#{@role}/#{@key}".camelize %>Controller
   self.resources = <%= @klass_name %>
 end