laravel accessing global variables in app.configfile

here is my config/app.php file contents;

<?php

return [

    'googlesecretkey'=>'6LdCG...

I am able to get data with 'Config::get('app.googlesecretkey')' in debug mode but somehow laravel throws

Class 'Illuminate\Foundation\Auth\Config' not found

exception. I search on net but cant find anything that helps..

via Chebli Mohamed