title: Do Optaplanner Joiners work on LocalDateTime?
body: <p>I'm a little confused with Optaplanner Joiners and data types. Can someone clarify what data types Joiners work on?</p>
  <p>Specifically - will they work on LocalDateTime:</p>
  <pre><code>   ...
     Joiners.lessThanOrEqual( (lesson) -&gt; lesson.getTimeslot().getStartTime() )
     ...
  </code></pre>
  <p>where getStartTime() will return a LocalDateTime</p>
  <p>of is this a case where a filter is required?</p>