[1.7.x] Added database migration for contrib.sites.

refs #22170.

Backport of ec6e2eac60 from master

django/contrib/sites/migrations/0001_initial.py

@@ -0,0 +1,28 @@
+# -*- coding: utf-8 -*-
+from __future__ import unicode_literals
+
+from django.db import models, migrations
+from django.contrib.sites.models import _simple_domain_name_validator
+
+
+class Migration(migrations.Migration):
+
+    dependencies = []
+
+    operations = [
+        migrations.CreateModel(
+            name='Site',
+            fields=[
+                ('id', models.AutoField(verbose_name='ID', serialize=False, auto_created=True, primary_key=True)),
+                ('domain', models.CharField(max_length=100, verbose_name='domain name', validators=[_simple_domain_name_validator])),
+                ('name', models.CharField(max_length=50, verbose_name='display name')),
+            ],
+            options={
+                'ordering': ('domain',),
+                'db_table': 'django_site',
+                'verbose_name': 'site',
+                'verbose_name_plural': 'sites',
+            },
+            bases=(models.Model,),
+        ),
+    ]