Matt is the one who has to do it, but has not been successful in past attempts.
EDIT: I think I found a hack. I sign in, then log out, then click on the link for Return to Special:Userlogin, then I click on Create an Account link and I get a screen where I can set up a new user. I seemed to be successfull creating a userid and password for cozwurth and GoMan (using TBA as email address). Please let me know if it works, then any registered user can set up an account for someone.
EDIT EDIT: it worked apparently, so we have ignition, Houston!
Production: 4.7.0-0.bpo.1-amd64, MX-15 RC1, AMD FX-4130 Quad-Core, GeForce GT 630/PCIe/SSE2, 8 GB, Kingston SSD 120 GB and WesternDigital 1TB
Testing: AAO 722: 3.16-0-4-686-pae. MX-15, AMD C-60 APU, 4 GB