Now that we have our fancy new VPS and are allowed to create multiple user accounts, I’ve run into a problem with basic linux permissions that you really only find when you have multiple users working in the same space. In my case, we need multiple users to have access to all of our online property web roots. I started by using chown to force the entire web root under the ownership of www-data:www-data and adding everyone who needed access to the secondary www-data group. This works fine until people start making changes. Each new file they write becomes owned by only them and their primary group.