/**
  * Adds a plugin, activates it and registers it with the event dispatcher
  *
  * @param PluginInterface $plugin plugin instance
  */
 public function addPlugin(PluginInterface $plugin)
 {
     $this->plugins[] = $plugin;
     $plugin->activate($this->composer, $this->io);
     if ($plugin instanceof EventSubscriberInterface) {
         $this->composer->getEventDispatcher()->addSubscriber($plugin);
     }
 }