models: Create DefaultStreamGroup.

zerver/migrations/0113_default_stream_group.py

@@ -0,0 +1,29 @@
+# -*- coding: utf-8 -*-
+# Generated by Django 1.11.5 on 2017-10-14 15:12
+from __future__ import unicode_literals
+
+from django.db import migrations, models
+import django.db.models.deletion
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('zerver', '0112_index_muted_topics'),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name='DefaultStreamGroup',
+            fields=[
+                ('id', models.AutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('name', models.CharField(db_index=True, max_length=60)),
+                ('realm', models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, to='zerver.Realm')),
+                ('streams', models.ManyToManyField(to='zerver.Stream')),
+            ],
+        ),
+        migrations.AlterUniqueTogether(
+            name='defaultstreamgroup',
+            unique_together=set([('realm', 'name')]),
+        ),
+    ]

zerver/models.py

@@ -1743,6 +1743,23 @@ class DefaultStream(models.Model):
     class Meta(object):
         unique_together = ("realm", "stream")
 
+class DefaultStreamGroup(models.Model):
+    MAX_NAME_LENGTH = 60
+    name = models.CharField(max_length=MAX_NAME_LENGTH, db_index=True)  # type: Text
+    realm = models.ForeignKey(Realm, on_delete=CASCADE)  # type: Realm
+    streams = models.ManyToManyField('Stream')  # type: Manager
+
+    class Meta(object):
+        unique_together = ("realm", "name")
+
+    def to_dict(self):
+        # type: () -> Dict[str, Any]
+        return dict(name=self.name, streams=[stream.to_dict() for stream in self.streams.all()])
+
+def get_default_stream_groups(realm):
+    # type: (Realm) -> List[DefaultStreamGroup]
+    return DefaultStreamGroup.objects.filter(realm=realm)
+
 class AbstractScheduledJob(models.Model):
     scheduled_timestamp = models.DateTimeField(db_index=True)  # type: datetime.datetime
     # JSON representation of arguments to consumer