I have a simple PHP app that allows a few users to input the data to the database. The app is behind Cloudflare Zero Trust, that I have integrated with our Google Workspace via Google IAM. I want to be able to pass the information about the user to my app (in SSO style) so that the user does not have to log on to the app itself, but for the app to be aware which user is doing what. Could anyone nudge me in a direction that will help me achieve it? Thanks in advance.