Merge branch 'appointments-dev' of...

Merge branch 'appointments-dev' of https://git-r3lab.uni.lu/piotr.atyjaszyk/scheduling-system into appointments-dev

smash/web/models.py

@@ -431,7 +431,6 @@ class Appointment(models.Model):
     )
     appointment_types = models.ManyToManyField(AppointmentType,
         verbose_name='Appointment types',
-        null=True, blank=True
     )
     room = models.ForeignKey(Room,
         verbose_name='Room ID',