preregistration: Add field to track import progress.

We add a field to track user's progress and other details
during the import process.

zerver/migrations/0629_preregistrationrealm_data_import_metadata.py

@@ -0,0 +1,20 @@
+# Generated by Django 5.0.9 on 2024-11-21 02:32
+
+import django.core.serializers.json
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+    dependencies = [
+        ("zerver", "0628_remove_realm_invite_to_realm_policy"),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name="preregistrationrealm",
+            name="data_import_metadata",
+            field=models.JSONField(
+                default=dict, encoder=django.core.serializers.json.DjangoJSONEncoder
+            ),
+        ),
+    ]

zerver/models/prereg_users.py

@@ -1,4 +1,5 @@
 from django.contrib.contenttypes.fields import GenericRelation
+from django.core.serializers.json import DjangoJSONEncoder
 from django.db import models
 from django.db.models import CASCADE, Q, QuerySet
 from django.db.models.functions import Upper
@@ -49,6 +50,8 @@ class PreregistrationRealm(models.Model):
         UserProfile, null=True, related_name="+", on_delete=models.SET_NULL
     )
 
+    data_import_metadata = models.JSONField(default=dict, encoder=DjangoJSONEncoder)
+
 
 class PreregistrationUser(models.Model):
     # Data on a partially created user, before the completion of