hasOne relationship modeling in Eloquent

test.php

// $app->user is a \UserFrosting\User object  
  
// This works
$tutor = \UserFrosting\Tutor::where('user_id', $app->user->id)->first();
error_log($tutor->first_name);

// This does not
error_log(print_r($app->user->tutor->first_name, true));

Tutor.php

namespace UserFrosting;

class Tutor extends UFModel {
    
    /**
     * Get the User object for this Tutor.
     */
    public function user() {
        return $this->belongsTo('UserFrosting\User');
    }
}

User.php

namespace UserFrosting;

// UFModel extends Eloquent\Model
class User extends UFModel {

  public function tutor(){
    return $this->hasOne('UserFrosting\Tutor');
  }
}