Automatically add new user to a specific App

[DucV]

Hi, 

I'm looking for a way to automated add new user to a specific Appsheet app.

The user flow is likely below:

1. User sign up to a form such as Google Form or/an on Appsheet form. The submitions is includes user's email.
2. User will be auto grant the permission to access a specific app. 

It seems that the API currently does not support this feature. That's why I post here with a hope that you guys may have a alternative solution. 

Thanks, 

Danny