Vulcan/server/publications/users_dashboard.js

// Publish all users to reactive-table (if admin)
// Limit, filter, and sort handled by reactive-table.
// https://github.com/aslagle/reactive-table#server-side-pagination-and-filtering-beta

ReactiveTable.publish("all-users", function() {
  if(isAdminById(this.userId)){
    return Meteor.users;
  } else {
    return [];
  }
});