Tailing MediaGoblin's Postfix logs - troubleshooting Trac emails to ticket requestor

[Ben Sturmfels]

Hi Simon,

When I create a test user on Trac, then add a new ticket as the test
user and reply to the ticket from my admin user, I'd expect the test
user to get an email, but that doesn't seem to come through.

Before I fiddle too much with Trac settings, I'd like to see what's
hitting Postfix, just to make sure it's not caused by my email spam
filtering. When I run:

/root/docker-compose-venv/bin/docker-compose up --build --force-recreate
--no-deps postfix

I don't seem to get the Postfix logs showing up like I was hoping. Can
you tell me how I can tail mail.log file please?

Cheers,
Ben