public void FollowUser(string handle, string streamName)
        {
            TwitterStream ts = streamManager.GetStream(streamName);

            if (ts != null)
            {
                if (!ts.AddPriorityUser(handle))
                {
                    Clients.Caller.invalidUser("That user does not exist!");
                }
                else
                {
                    GetPriorityUsers(streamName);
                }
            }
        }