added support for fractions

cookbook/migrations/0090_auto_20201214_1359.py

@@ -0,0 +1,24 @@
+# Generated by Django 3.1.3 on 2020-12-14 12:59
+
+import datetime
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('cookbook', '0089_auto_20201117_2222'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='userpreference',
+            name='use_fractions',
+            field=models.BooleanField(default=False),
+        ),
+        migrations.AlterField(
+            model_name='invitelink',
+            name='valid_until',
+            field=models.DateField(default=datetime.date(2020, 12, 28)),
+        ),
+    ]