如何在移动应用程序中使用Joomla用户数据库？

I'm coding a website for a client as well as an app that mirrors the site. Does anyone have a good understanding on how to implement users created on the Joomla site and use that same database on an App for android? The app and site will allow users to change and add new data and the data must be current on the site and the app. I'm coding a website for a client as well as an