How do i configure the pubsub service?

In the source code for the PubSubModule I see that there is the following:

     * Bare jids of users that are system administrators of the PubSub service. A sysadmin
     * has the same permissions as a node owner.
    private Collection<String> sysadmins = new CopyOnWriteArrayList<String>();

How do I configure this? Or more generic, how do I configure modules?