class Route(models.Model):
    distance = models.FloatField(verbose_name='Дистанция')
    route_from = models.ForeignKey(City, on_delete=models.CASCADE, verbose_name='Откуда', related_name='routes_from')
    route_to = models.ForeignKey(City, on_delete=models.CASCADE, verbose_name='Куда',
                                 related_name='routes_to')


class Travel(models.Model):
    departure_time = models.DateTimeField(verbose_name='Время выезда')
    arrival_time = models.DateTimeField(verbose_name='Время приезда', null=True, blank=True)
    fare = models.PositiveIntegerField(verbose_name='Цена')
    bus = models.ForeignKey(Bus, verbose_name='Автобус', related_name='travels', on_delete=models.CASCADE)
    route = models.ForeignKey(Route, verbose_name='Маршрут', related_name='travels', on_delete=models.CASCADE)