Add "user" as a field option for custom fields

It would be really helpful to be able to have “users” as an option for custom fields. That way you could have other roles associated with an incident, and capture them. The alternative is to choose “single select” and then manually add all users (to a max of 200). Bonus points if you can define if adding someone adds them as a responder or stakeholder to the incident (but not essential for MVP)