models: Add message_visibility_limit attribute to Realm.

zerver/migrations/0132_realm_message_visibility_limit.py

@@ -0,0 +1,20 @@
+# -*- coding: utf-8 -*-
+# Generated by Django 1.11.6 on 2018-01-03 18:14
+from __future__ import unicode_literals
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('zerver', '0131_realm_create_generic_bot_by_admins_only'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='realm',
+            name='message_visibility_limit',
+            field=models.IntegerField(null=True),
+        ),
+    ]

zerver/models.py

@@ -173,6 +173,7 @@ class Realm(models.Model):
     waiting_period_threshold = models.PositiveIntegerField(default=0)  # type: int
     DEFAULT_MAX_INVITES = 100
     max_invites = models.IntegerField(default=DEFAULT_MAX_INVITES)  # type: int
+    message_visibility_limit = models.IntegerField(null=True)  # type: int
 
     # Define the types of the various automatically managed properties
     property_types = dict(