Missing controller

You are seeing this error because controller ShopController could not be found.

Notice: this error is being rendered by the app/views/errors/missing_controller.thtml view file, a user-customizable error page for handling invalid controller dispatches.

Fatal: Unable to load controller ShopController

Fatal: Create Class:

<?php
class ShopController extends AppController
{
var $name = 'Shop';
}
?>

in file : app/controllers/shop_controller.php