public IEnumerable <Appointment> List()
        {
            var appointments = new VetDbContext().Appointments.Include(p => p.Doctor).Include(p => p.Room).Include(p => p.Patient);

            return(appointments.ToList());
        }
        public IEnumerable <Patient> List()
        {
            var patients = new VetDbContext().Patients.Include(p => p.Owner);

            return(patients.ToList());
        }