Add option to be notified when a followed user posts (#13546)

* Add bell button

Fix #4890

* Remove duplicate type from post-deployment migration

* Fix legacy class type mappings

* Improve query performance with better index

* Fix validation

* Remove redundant index from notifications

1 files changed, 22 insertions, 0 deletions

diff --git a/db/post_migrate/20200917193528_migrate_notifications_type.rb b/db/post_migrate/20200917193528_migrate_notifications_type.rb
new file mode 100644
index 000000000..88e423084
--- /dev/null
+++ b/db/post_migrate/20200917193528_migrate_notifications_type.rb
@@ -0,0 +1,22 @@
+# frozen_string_literal: true
+
+class MigrateNotificationsType < ActiveRecord::Migration[5.2]
+  disable_ddl_transaction!
+
+  TYPES_TO_MIGRATE = {
+    'Mention'       => :mention,
+    'Status'        => :reblog,
+    'Follow'        => :follow,
+    'FollowRequest' => :follow_request,
+    'Favourite'     => :favourite,
+    'Poll'          => :poll,
+  }.freeze
+
+  def up
+    TYPES_TO_MIGRATE.each_pair do |activity_type, type|
+      Notification.where(activity_type: activity_type, type: nil).in_batches.update_all(type: type)
+    end
+  end
+
+  def down; end
+end