Lumen environments definition

I have used Lumen (Laravel based framework) to design my API.

I must manage two environments (production, local). I tried to put these lines in my bootstrap/app.php file :

$env = $app->detectEnvironment(array( 'local' => array('my-system'), 'production' => array('prod-system'), )); But, when I try to execute php artisan serve it gives me the following error :

Call to undefined method Laravel\Lumen\Application::detectEnvironment() How can I define my environments in Lumen ?