diff --git a/app/models/concerns/notifiable.rb b/app/models/concerns/notifiable.rb
new file mode 100644
index 00000000000..722f375e71d
--- /dev/null
+++ b/app/models/concerns/notifiable.rb
@@ -0,0 +1,15 @@
+# == Notifiable concern
+#
+# Contains notification functionality shared between UsersProject and UsersGroup
+#
+module Notifiable
+  extend ActiveSupport::Concern
+
+  included do
+    validates :notification_level, inclusion: { in: Notification.project_notification_levels }, presence: true
+  end
+
+  def notification
+    @notification ||= Notification.new(self)
+  end
+end