Call to a member function set() on null

I am trying to use oauth for google in laravel 5 but i am getting the error. Can any one help me to sort out this problem.

//Followings are my files please check out

.env

GOOGLE_ID = 'mygoogleId'

GOOGLE_SECRET = 'mysecretID'

GOOGLE_REDIRECT = http://localhost:8090/users

services.php

'google' => [

    'client_id' => env('GOOGLE_ID'),
    'client_secret' => env('GOOGLE_SECRET'),
    'redirect' => env('GOOGLE_REDIRECT'),
],

AuthController

public function redirectToProvider() {

    return Socialite::driver('google')->redirect();

}

public function handleProviderCallback() {

    $user = Socialite::driver('google')->user();
        console.log($user);

}

routes.php

Route::get('google', 'Auth\AuthController@redirectToProvider');

Route::get('google/callback', 'Auth\AuthController@handleProviderCallback');

//I have set the providers and aliases in app.php.

Thanks in advance..

via Chebli Mohamed