models: Add enable_read_receipts organization setting field.

zerver/migrations/0404_realm_enable_read_receipts.py

@@ -0,0 +1,18 @@
+# Generated by Django 4.0.6 on 2022-08-04 07:38
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ("zerver", "0403_create_role_based_groups_for_internal_realms"),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name="realm",
+            name="enable_read_receipts",
+            field=models.BooleanField(default=False),
+        ),
+    ]

zerver/models.py

@@ -684,6 +684,10 @@ class Realm(models.Model):
 
     default_code_block_language: Optional[str] = models.TextField(null=True, default=None)
 
+    # Whether read receipts are enabled in the organization. If disabled,
+    # they will not be available regardless of users' personal settings.
+    enable_read_receipts: bool = models.BooleanField(default=False)
+
     # Define the types of the various automatically managed properties
     property_types: Dict[str, Union[type, Tuple[type, ...]]] = dict(
         add_custom_emoji_policy=int,