/**
  * @param Reaction $reaction
  */
 public function process(Reaction $reaction)
 {
     // Only process reaction on saved links
     $link = $this->linkRepository->findOneBySlackMessageId($reaction->getMessageId());
     if (!$link instanceof Link) {
         return;
     }
     $user = $this->userRepository->findOneBySlackId($reaction->getUserId());
     if (!$user instanceof User) {
         $this->logger->error(sprintf('User "%s" not found', $reaction->getUserId()));
         return;
     }
     if ($reaction->isLike()) {
         $link->likedBy($user);
     }
     if ($reaction->isDislike()) {
         $link->dislikedBy($user);
     }
     $this->objectManager->flush();
     $this->objectManager->clear();
 }