The application creates a new user with limited rights: it can connect (with a password) through SFTP to access the `/var/www/my_webapp` directory (or `/var/www/my_webapp__<number>` if there are several installations of this application).
This configuration requires updating the site content manually, with a password connection.
If you want to automate things, you need to be able to connect without typing a password (i.e. "non-interactive"). Here are the steps to follow to get there: