Option to invite users via Email

[tvvignesh]

It would be great to have the ability for admins to invite other users to the repo to signup over mail.
Currently, we are doing this by sharing the repository URL and asking them to sign up but would be good to have an email invite option.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs during the next 2 weeks. Thank you for your contributions.

[tobiasBora]

Also interested !

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs during the next 2 weeks. Thank you for your contributions.

[lunny]

We can add an option to invitation signup mode. Enable invitation number in app.ini and default to zero.
We need a table to save the invitation emails and inviters. And when the signup mode is invitation, only the user whose email on that table could be registered successfully.