Easyest way to use external database to log in WordPress

This plugin is awesome. It saves my life !
I can use a different database than the WordPress one.

I have an application that automatically creates user and password when user subscribes to the app and with this plugin no need to recreate user in WordPress it is totally automatic.

If user changes password in my main app, when he tries to connect to WordPress with his new password it logins without any other action.

And cherry on the cake, the author is ready to help us when we are have any problem.
He can be proud of his plugin.
Great job !