def groups_with_users
      groups.reduce({}) do |list, group|
        list[group] = redis.smembers(group).map do |user_id|
          User.find_by_id(user_id)
        end
        list
      end
    end
def groups_with_users
      groups.reduce({}) do |list, group|
        list[group] = redis.smembers(group).map do |user_id|
          User.find_by_id(user_id)
        end
        list
      end
    end
Returns a hash of authorization group names and the users in them.
 @return [Hash] A map of +Symbol+ group names to {User} objects.