command like
        <code>/ab add Jack star</code>, it will first remove the <code>star</code> category
        from all other users and then add it to <code>Jack</code>.</p>
    
    <p>If you want to have more than one unique category, you can separate
        several categories by comma: <code>/set abUniqueCats star,gold</code></p>
    
    
    <h3><a name="subs-cats">Automatic Subscriber Categories</a></h3>
    <p>This is an experimental feature that adds Subscribers automatically to
        an Addres