title: Register fetched data (not in database) in Timber PostQuery
body: <p>I am currently developing for a site that uses Timber in Wordpress. I am using an API of a different site to fetch posts from a different site, so they are up to date with the current state on that site. The problem is that I’m using the post title field to fetch the correct ID from the API. This means that no title or content data is stored in the database.</p>
  
  <p>Is there a way I can register this data so that Timber PostQuery objects will also fetch these pages properly? I am unable to access or alter the result of <code>$result = new Timber\PostQuery()</code> afterwards, since these fields are protected and private.</p>
  
  <p>Thanks in advance!</p>