Add processing site migration

ldvspec/lofardata/migrations/0006_atdbprocessingsite_workspecification_processing_site.py

+# Generated by Django 4.1 on 2022-08-10 15:56
+
+from django.db import migrations, models
+import django.db.models.deletion
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('lofardata', '0005_include_work_specification'),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name='ATDBProcessingSite',
+            fields=[
+                ('name', models.CharField(max_length=100, primary_key=True, serialize=False)),
+                ('url', models.URLField()),
+            ],
+        ),
+        migrations.AddField(
+            model_name='workspecification',
+            name='processing_site',
+            field=models.ForeignKey(null=True, on_delete=django.db.models.deletion.DO_NOTHING, to='lofardata.atdbprocessingsite'),
+        ),
+    ]