Do out of the box user management tools exist?

I have a database (cloudant) with account info and other things that would typically be stored in a database for an application. I can go build a custom admin portal to access the database for business users to "approve" users or add/change information - but I was hoping there would be tools that can connect to a database and provide a simple interface for CRUD actions to admin users.

Does anything like this exist in the market today?

Thanks for your response. That's just for authentication though, right?