I've set up a webhook for GitHub on one of my domains. It was working just fine until it it stopped and started generating a permission error. After investigating, I figured out what was happening. When I began, php files were being executed by the "web31" user, the owner of that domain. Now they are being executed by the "apache" user, which obviously does not have ownership of the files in the web root. I have not changed any server settings. Why has this changed?