title: Laravel 5 - Task schedule withoutOverlapping not working
body: <p>I try to run schedule on Laravel 5. Its work fine when I run this:</p>
  
  <pre><code>$schedule-&gt;call(function() {
     // do something here..
  })-&gt;everyMinute();
  </code></pre>
  
  <p>But when I add <code>withoutOverlapping()</code>, the scheduler never run the task:</p>
  
  <pre><code>$schedule-&gt;call(function () {
     // do something here..
  })-&gt;everyMinute()-&gt;name('job_name')-&gt;withoutOverlapping();
  </code></pre>
  
  <p>*these schedule code is written at /app/Console/Kernel.php</p>