gistfile1.txt

$app->register(
    new Silex\Provider\SwiftmailerServiceProvider(),
    array(
        'swiftmailer.options' => array(
            'sender_address' => $sender,
            'transport' => 'smtp',
            'encryption' => null,
            'auth_mode' => 'login',
            'host' => $server,
            'port' => $port',
            'username' => $user,
            'password' => $pass
        )
    )
);

$app['mailer']->registerPlugin(new Swift_Plugins_RedirectingPlugin($dev_email_address));