Change custom_cards to allow null and blank

@@ -0,0 +1,18 @@# Generated by Django 4.0.5 on 2022-06-23 23:11from django.db import migrations, modelsclass Migration(migrations.Migration):    dependencies = [        ('properties', '0002_initial_data'),    ]    operations = [        migrations.AlterField(            model_name='property',            name='custom_cards',            field=models.JSONField(blank=True, default=list, null=True),        ),    ]

@@ -15,7 +15,7 @@ class Property(models.Model):    id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)    user = models.ForeignKey(User, on_delete=models.CASCADE, related_name='properties')    name = models.CharField(max_length=255)    custom_cards = models.JSONField(default=list)    custom_cards = models.JSONField(default=list, blank=True, null=True)    created_at = models.DateTimeField(auto_now_add=True, editable=False)    updated_at = models.DateTimeField(auto_now=True, editable=False)    is_protected = models.BooleanField(default=False, editable=False)