$app = new SlimApp();
$app->POST('/user/login', function($request, $response, $args) {

    $queryParams = $request->getQueryParams();
    $username = $queryParams['username'];
    $password = $queryParams['password'];

    $response->write("Will not work");
    return $response;
});
$app->GET('/user/{user_id}', function($request, $response, $args) {

    $response->write('Works');
    return $response;
});