title: add a file to a folder inside a zip file using PHP
body: <p>How can I add a file to a folder inside a zip file using PHP?</p>
  
  <p>For example if I have the zip file:</p>
  
  <pre><code>myzip.zip
    |-hello.doc
  </code></pre>
  
  <p>If I wanted to add the file "example.jpg" inside the "images" folder, the zip file would be:</p>
  
  <pre><code>myzip.zip
    |-hello.doc
    |-images
      |-example.jpg
  </code></pre>
  
  <p>How can I achieve this?</p>