Readme - documentation link.

README.md

@@ -57,3 +57,7 @@ $notice = new \WPDesk\Notice\Notice('Notice text goes here');
 ```
 
 Notice must be used before WordPress action `admin_notices`. WordPress admin actions order is listed [here](https://codex.wordpress.org/Plugin_API/Action_Reference#Actions_Run_During_an_Admin_Page_Request).
+
+## Project documentation
+
+https://wpdesk.gitlab.io/wp-notice/index.html