Is your proposal related to a problem?

Currently, signups cannot be disabled.

This may be a problem for deployments that don't wish to allow new users (manually managed teams, individual people using a full deployment for their own schedule).

Describe the solution you'd like

A first-class feature to disable signups.

Some of the things this would do include:

• Remove the link on the login page
• Make the form inaccessible if someone tried to access it directly
• Prevent any new user creation via API

Describe alternatives you've considered

Editing source files