title: In PHP, how do I add 3 months to the purchase date retrieved from the iPhone InApp receipt?
body: <p>After I have validated the receipt against the App Store from my PHP server, the App Store sends me back a JSON response with</p>
  
  <pre><code>"status" : 0 
  "receipt" : ( .... )
  </code></pre>
  
  <p>One of the receipt items is "purchase_date" which contains the following string (example) "2010-02-09 19:17:04 Etc/GMT"</p>
  
  <p>I'm trying to establish a subscription service and would like to add 3 months to this date and then write that expiry date into a MySQL table. </p>
  
  <p>Is there a string-to-date type function in PHP that can allow me to achieve the adding of 3 months? </p>
  
  <p>I have found this example which looks like it adds 1 month to a date:</p>
  
  <pre><code>$date = date("Y-m-d");// current date
  $date = strtotime(date("Y-m-d", strtotime($date)) . " +1 month");
  </code></pre>
  
  <p>But I'm not sure how I can turn the string passed by the App Store into a PHP recognised date. </p>