public Guid Login(string user, string pass)
        {
            using (DataAccessLayer dal = new EFDataAccessLayer())
            {
                var userDto = dal.PersonDAO.ReadAll().SingleOrDefault(o => o.Email == user);

                if (userDto == null || !userDto.Password.Equals(pass))
                {
                    return Guid.Empty;
                }
            }

            // Em caso afirmativo, criar o ticket
            Ticket t = new Ticket(Guid.NewGuid(), DateTime.Now.AddMinutes(2));

            currTickets.Add(t.TicketId,t);

            return t.TicketId;
        }
        public Guid Login(int userID, string pass)
        {
            // Validar utilizador
            using (DataAccessLayer dal = new EFDataAccessLayer())
            {
                var user = dal.PersonDAO.Read(userID);

                if (user == null || !user.Password.Equals(pass))
                {
                    return Guid.Empty;
                }
            }

            // Em caso afirmativo, criar o ticket
            Ticket t = new Ticket(Guid.NewGuid(), DateTime.Now.AddMinutes(2));

            currTickets.Add(t.TicketId,t);

            return t.TicketId;
        }