misc fixes and updates

cookbook/migrations/0004_auto_20180515_2035.py

@@ -0,0 +1,19 @@
+# Generated by Django 2.0.5 on 2018-05-15 18:35
+
+from django.db import migrations, models
+import django.db.models.deletion
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('cookbook', '0003_auto_20180514_1121'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='recipe',
+            name='category',
+            field=models.ForeignKey(blank=True, null=True, on_delete=django.db.models.deletion.SET_NULL, to='cookbook.Category'),
+        ),
+    ]