fixed several shopping list issues

cookbook/migrations/0082_auto_20200922_1143.py

@@ -0,0 +1,24 @@
+# Generated by Django 3.0.7 on 2020-09-22 09:43
+
+import datetime
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('cookbook', '0081_auto_20200921_2349'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='invitelink',
+            name='valid_until',
+            field=models.DateField(default=datetime.date(2020, 10, 6)),
+        ),
+        migrations.AlterField(
+            model_name='shoppinglistentry',
+            name='amount',
+            field=models.DecimalField(decimal_places=16, default=0, max_digits=32),
+        ),
+    ]