code: def forward(apps, schema_editor):
      
  
      Event = apps.get_model('spectator_events', 'Event')
      MovieSelection = apps.get_model('spectator_events', 'MovieSelection')
      PlaySelection = apps.get_model('spectator_events', 'PlaySelection')
  
      for event in Event.objects.all():
          if event.movie is not None:
              selection = MovieSelection(event=event, movie=event.movie)
              selection.save()
  
          if event.play is not None:
              selection = PlaySelection(event=event, play=event.play)
              selection.save()
docs: Copying data from the old `Event.movie` and `Event.play` ForeignKey fields
      into the new `Event.movies` and `Event.plays` ManyToManyFields.