Laravel\Lumen\Application::register PHP Method

    public function register($provider, $options = [], $force = false)
    {
        if (!$provider instanceof ServiceProvider) {
            $provider = new $provider($this);
        }
        if (array_key_exists($providerName = get_class($provider), $this->loadedProviders)) {
            return;
        }
        $this->loadedProviders[$providerName] = true;
        if (method_exists($provider, 'register')) {
            $provider->register();
        }
        if (method_exists($provider, 'boot')) {
            return $this->call([$provider, 'boot']);
        }
    }

 /**
  * Register the service providers from this plugin.
  */
 protected function registerProviders()
 {
     foreach ($this->get('providers', []) as $provider) {
         $this->app->register($provider);
     }
 }