title: Adding script to OpenCart
body: <p>In creating a module I'm trying to avoid overwriting files and I would like to add JS script to OpenCart head section inside the admin area. I do this inside the module I created.</p>
  
  <p>In the controller I added</p>
  
  <pre><code>$this-&gt;document-&gt;addScript('my-script.js'); 
  $this-&gt;document-&gt;addStyle('my-style.css');
  </code></pre>
  
  <p>This works only on the module edit page, not everywhere. How do I do it so it gets added to all pages inside the OpenCart admin area?</p>