Should each site run as its own user?

Question

linux

Which approach is correct:

1. All web projects (php, java ee) run as a user who is in the www-data group
   
2. Each site has its own user, the --disable-login user and in the www-data group
   
3. For different platforms, their users php - userphp, rails - userails
   

Now on the server for my needs (not hosting) I work on 3 points, projects on laravel, yii and wp work from the webuser user who is in the www-data group
Under Redmine (ERP) which works on Ruby / Rails, a separate redmine user, who also is included in the www-data group
Where can I read more about this?

Answer 1

It is most convenient to run nginx from www-data, but the http-pool itself is already from the user.
So there will be no problems with the rights.