change JSONField to postgres JSONField to work with json blobs

ldvspec/lofardata/migrations/0014_alter_dataproduct_additional_meta.py

+# Generated by Django 3.2 on 2022-12-15 15:01
+
+import django.contrib.postgres.fields.jsonb
+from django.db import migrations
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('lofardata', '0013_auto_20221214_1338'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='dataproduct',
+            name='additional_meta',
+            field=django.contrib.postgres.fields.jsonb.JSONField(),
+        ),
+    ]

ldvspec/lofardata/models.py

 import logging
 from celery.result import AsyncResult
 from django.contrib.auth.models import User
-from django.contrib.postgres.fields import ArrayField
+from django.contrib.postgres.fields import ArrayField, JSONField
 from django.db import models, IntegrityError
 from django.utils.translation import gettext_lazy as _
-
 logger = logging.getLogger(__name__)
 
 
@@ -18,7 +17,7 @@ class DataProduct(models.Model):
     activity = models.CharField(max_length=50)
     surl = models.CharField(max_length=200, unique=True)
     filesize = models.PositiveBigIntegerField()
-    additional_meta = models.JSONField()
+    additional_meta =  models.JSONField
 
     @staticmethod
     def insert_dataproduct(