If you have to work with a LAMP stack one of the first things you do is setting up permission for your user and web server so that you can deploy files correctly and securely and also ina. way that the server can read and execute them. This often becomes a headache quickly when the two user groups require specific permission sets on specific files to work securely. The most popular solution Almost every StackOverflow answer and suggested method will involve giving developers the same user group access as the webserver. Most commonly it's access to www-data . This however comes with it's own set of baggage. If you have several web applications running side-by-side on your web server, you'll have to juggle a lot more with groups and sub-groups just to prevent Developer A to be able to see and modify Application B. When a developer creates a file, the file is owned by the developer, and might not be readable (nor writable if needed) properly by the webserve...
This is my mindless rambling.