title: Adding 1 hour to time variable
body: <p>I have a time to which I want to add an hour:</p>
  <pre><code>$time = '10:09';
  </code></pre>
  <p>I've tried:</p>
  <pre><code>$time = strtotime('+1 hour');
  
  strtotime('+1 hour', $time);
  
  $time = date('H:i', strtotime('+1 hour'));
  </code></pre>
  <p>But none of the above work.</p>