Configuration UI for Merge check - help with getting User selector working

So this is probably pretty simple but I can’t seem to find a solution for it. Basically, I made a RepositoryMergeCheck plugin for BitBucket Server and now, instead of hardcoding my values for which branches to check and who is allowed to do things, I want the values to come from configuration.

I am able to make a basic config screen which I got from the examples (it’s a soy template) but I’m not sure how to get a user list and allow multiple people to be selected at once. I could type the usernames in manually but I’m looking for a way to have it show the users in a selectable list. I saw a post on here talking about a JS plugin user-and-group-multi-selector.js but I have no idea how to use it or what to call and I guess it’s an internal API that could change?

Ideas on what the best approach is?