Fix weekday field access.

biscuit/apps/chronos/views.py

@@ -31,8 +31,8 @@ def timetable(request: HttpRequest, year: Optional[int] = None, week: Optional[i
         wanted_week = CalendarWeek()
 
     lesson_periods = LessonPeriod.objects.filter(
-        lesson__date_start__lte=wanted_week[0] + timedelta(days=1) * F('weekday') - 1,
-        lesson__date_end__gte=wanted_week[0] + timedelta(days=1) * F('weekday') - 1
+        lesson__date_start__lte=wanted_week[0] + timedelta(days=1) * F('period__weekday') - 1,
+        lesson__date_end__gte=wanted_week[0] + timedelta(days=1) * F('period__weekday') - 1
     ).select_related(
         'lesson', 'lesson__subject', 'period', 'room'
     ).prefetch_related(