add created_at to user model

services/backend/apps/user/migrations/0002_user_created_at.py

@@ -0,0 +1,18 @@
+# Generated by Django 5.1.6 on 2025-03-02 09:50
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('user', '0001_initial'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='user',
+            name='created_at',
+            field=models.DateTimeField(auto_now=True),
+        ),
+    ]