You can manually manage user registration using the command line utility. Please see the command line documentation for installing and configuring the command line utility.
ls command to list all active users:
drone user ls
add command to add users to the system by login:
drone user add octocat
rm command to remove users from the system by login:
drone user rm octocat
Please note that only drone administrators can manage users. Please see the below example to configure one or many administrators, separated by a comma, using the designated environment variable.
services: drone-server: image: drone/drone:0.5 environment: + DRONE_ADMIN: janedoe,johnsmith