Missing controller

You are seeing this error because controller ArticlesController 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 ArticlesController

Fatal: Create Class:

<?php
class ArticlesController extends AppController
{
var $name = 'Articles';
}
?>

in file : app/controllers/articles_controller.php