Symfony's configuration system has improved *a lot* in recent years. Let's step
back and look at how we can tackle all of the most common problems using the new
approaches! This will include tricks for configuring services as *easily* as possible,
handling different environment configuration and the hugely important topic of
environment variables and secrets. We'll discuss both practical approaches to handling
environment variables on production as well as best-practices for deploying a super
secure app.