Keep this plugin at the top and with the folder named "ufcoe_roles".
Do not load your class until your init() function, as the UFCOE_RoleProvider won't be loaded until the init stage.
Add your providers in your init(), but ideally don't try to fetch roles until after the system/init phase has ended (to make sure other plugins have had a change to add their providers).
The Elgg provider is automatically added, so admins will get the "elgg:admin" role.