You can find the full source code for this website in the Seam package in the directory /examples/wiki. It is licensed under the LGPL.
If you are an existing committer, you may want to bring in another person to help you out. To do that, you'll need to follow these steps:
Developerrole in JIRA for the relevant modules. To do this, choose Administer Project -> View Members -> Developers / Edit. You should use the user picker to find the user (there is a bug in JIRA whereby an incorrect username entered causes a NullPointerException when using this screen in the future - if you do make this mistake, you need to contact mailto:helpdesk.AT.redhat.com and ask for the database to be fixed).
At this point the new committer should be ready to go. Make sure you are around to review their initial commits!