allow 'sudo' from browser for script

if you want to execute a script by browser input, you need to allow the webserver-user 'www-data' to use 'sudo' without the need to use sudo-password.

Therefore you use 'visudo' to edit /etc/sudoers, and add the follwing line at the end of the file:

www-data ALL=NOPASSWD: /home/YOUR_USER/YOUR_SCRIPT.sh