If you have a need to provide a current user with admin level permissions, simply follow these steps:
(Note: you will have to already have created the user as per this guide - Buzz - Adding Users)
1. From the main Admin App view, click on the Permissions tab
2. Click on the Add (plus icon) in the upper right
3. Enter the username in the User field.
4. By default, the Role is set to Administrator, so just click Save.