code: private static Tweets addTweets(User user, String body, Date tweetDate, String tweetId)
      {
          Tweets tweet = new Tweets();
          tweet.setTweetId(tweetId);
          tweet.setBody(body);
          tweet.setTweetDate(tweetDate);
          user.getTweets().add(tweet);
          return tweet;
      }
docs: /*
  Add user's tweets to provided user object.