title: PHP datetime add 6 months and 1 year
body: <p>I have a date set using PHP datetime like this..</p>
  
  <pre><code>$originaldate = 2019-01-10 17:52:17
  $converted = DateTime::createFromFormat("Y-m-d H:i:s", $originaldate);
  </code></pre>
  
  <p>The date is successfuly converted into a PHP DateTime object, now I am trying to add create 2 new dates that are 6 months and 1 year ahead of this date.</p>
  
  <p>Whats the best way to achieve this?</p>