Отправитель
usr_in_hour = []

usr_hour = Signal(providing_args=['usr_in_hour'])

class Command(BaseCommand):

    def handle(self, *args, **options):
        now = timezone.now()
        two_hour = now - datetime.timedelta(hours=2)
        MySession.objects.filter(expire_date__range=(two_hour, now)).delete()
        Session.objects.filter(expire_date__range=(two_hour, now)).delete()

        usr_hour.send(sender=self.__class__, usr_in_hour=usr_in_hour)

        self.stdout.write('Succes')

Получатель
@receiver(usr_hour, sender=Command)
def my_callback(sender, usr_in_hour, **kwargs):
    usr_in_hour.clear()
    boards = Board.objects.all().values('board_shortcut')
    for x in boards:
        usr_in_hour.append(MySession.objects.filter(name_board__contains=x['board_shortcut']).count())
Вьюха
from .management.commands.db_hour import usr_in_hour

# Create your views here.

def index(request):
    boards = Board.objects.all()
    for board in boards:
        board.board_posts = Thread.objects.filter(board=board).count() + Comment.objects.filter(thread__board=board).count()
    return render(request ,'index.html', {'boards': boards, 'usr_in_hour': usr_in_hour})