Remember Token not Working in Laravel Lumen

What I want is to clear the value of remember_token every time I sign out.

Here's my code in User.php

public function removeToken($token) {
    $information = $this->where('remember_token', $token)->firstOrFail();

    return $information;
}

And here's my UserController.php

public function signOut(Request $request, User $user) {
   $deletedToken = $user->removeToken($request->token);

   return response()->json($deletedToken);
}

Other functions inside of User.php that has a $this is working as expected, my question is why $this keyword return an empty object whehn I want to access the removeToken()?

This line of code is working as expected, it is inside of User.php also.

public function findEmail($email) {
   return $this->where('email', $email)->firstOrFail();
}

How can I solve my problem?

via Chebli Mohamed