code: public void init(ModeledAuthenticatedUser currentUser, UserGroupModel model,
              boolean exposeRestrictedAttributes) {
          super.init(currentUser, model);
          this.exposeRestrictedAttributes = exposeRestrictedAttributes;
      }
docs: Initializes this ModeledUserGroup, associating it with the current
  authenticated user and populating it with data from the given user group
  model.
  
  @param currentUser
  The user that created or retrieved this object.
  
  @param model
  The backing model object.
  
  @param exposeRestrictedAttributes
  Whether attributes which control access restrictions should be
  exposed via getAttributes() or allowed to be set via
  setAttributes().