Booking status specification

// Status of a booking.
//
// Updating booking status does not change the status of the associated payment.
// Prepayment status updates should be done using the PrepaymentStatus enum.
//
// nextID: 6
enum BookingStatus {
  // Not specified.
  BOOKING_STATUS_UNSPECIFIED = 0;

  // Booking has been confirmed
  CONFIRMED = 1;

  // ...
  CANCELED = 3;

  // User did not show for the appointment
  NO_SHOW = 4;

  // User did not show for the appointment in violation of the cancellation
  // policy.
  NO_SHOW_PENALIZED = 5;
}