title: What's the best way of adding a time interval in PHP?
body: <p>I want to add time to an existing date. I have 2 string variables:</p>
  
  <pre><code>$date     = "2013-01-05 10:55:15";
  $interval =            "50:25:10";
  </code></pre>
  
  <p>I want to calculate the final date "2013-01-07 13:20:25". The hours in time can be bigger than 23, meaning that this interval can be greater than a whole day.</p>
  
  <p>What's the best way to do this ?</p>