Update migrations for "created at" field

qsessions/migrations/0001_initial.py

@@ -1,5 +1,5 @@
 # -*- coding: utf-8 -*-
-# Generated by Django 1.11.2 on 2018-02-03 11:04
+# Generated by Django 1.11.2 on 2017-12-19 16:00
 from __future__ import unicode_literals
 
 from django.conf import settings
@@ -24,7 +24,6 @@ class Migration(migrations.Migration):
                 ('session_data', models.TextField(verbose_name='session data')),
                 ('expire_date', models.DateTimeField(db_index=True, verbose_name='expire date')),
                 ('user_agent', models.CharField(blank=True, max_length=300, null=True)),
-                ('created_at', models.DateTimeField()),
                 ('updated_at', models.DateTimeField(auto_now=True)),
                 ('ip', models.GenericIPAddressField(blank=True, null=True, verbose_name='IP')),
                 ('user', models.ForeignKey(null=True, on_delete=django.db.models.deletion.CASCADE, to=settings.AUTH_USER_MODEL)),

qsessions/migrations/0002_session_created_at.py

@@ -0,0 +1,20 @@
+# -*- coding: utf-8 -*-
+# Generated by Django 1.11.2 on 2018-02-05 06:55
+from __future__ import unicode_literals
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('qsessions', '0001_initial'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='session',
+            name='created_at',
+            field=models.DateTimeField(null=True),
+        ),
+    ]

qsessions/models.py

@@ -20,7 +20,7 @@ class Session(AbstractBaseSession):
     user = models.ForeignKey(getattr(settings, 'AUTH_USER_MODEL', 'auth.User'),
                              null=True, on_delete=models.CASCADE)
     user_agent = models.CharField(null=True, blank=True, max_length=300)
-    created_at = models.DateTimeField()
+    created_at = models.DateTimeField(null=True)
     updated_at = models.DateTimeField(auto_now=True)
     ip = models.GenericIPAddressField(null=True, blank=True, verbose_name=_('IP'))