Advanced data in timetable views

Closes #72 (closed) Closes #73 (closed)

aleksis/apps/chronos/migrations/0011_absence_for_groups_and_rooms.py

+# Generated by Django 3.0.5 on 2020-04-13 15:07
+
+from django.db import migrations, models
+import django.db.models.deletion
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('chronos', '0010_absence_reason_name'),
+    ]
+
+    operations = [
+        migrations.RemoveField(
+            model_name='absence',
+            name='person',
+        ),
+        migrations.AddField(
+            model_name='absence',
+            name='group',
+            field=models.ForeignKey(blank=True, null=True, on_delete=django.db.models.deletion.CASCADE, related_name='absences', to='core.Group'),
+        ),
+        migrations.AddField(
+            model_name='absence',
+            name='room',
+            field=models.ForeignKey(blank=True, null=True, on_delete=django.db.models.deletion.CASCADE, related_name='absences', to='chronos.Room'),
+        ),
+        migrations.AddField(
+            model_name='absence',
+            name='teacher',
+            field=models.ForeignKey(blank=True, null=True, on_delete=django.db.models.deletion.CASCADE, related_name='absences', to='core.Person'),
+        ),
+    ]