There is a bug in user handling the current release (0.2.0) of open-source Drone.IO. The only way of adding users to you Drone server (except yourself - that you add in the install process) is by inviting them via email. Problem is that the invitation emails lead to a form which requires the user to be logged in - a classic catch 22.
So here's a workaround to add users to the server and your team(s):
1. Enable open invitations (temporarily if your server is going to be private). 2. Have the users request their own invite on the login screen. 3. After the user accepts the invite, go into your team settings and invite them using the same email address they used to register. 4. After all users have registers, close open invitations if your server is private.
The invitation problem is alledgedly fixed in version 0.3.0, but that's not ready yet.