As others have said, remove the # to uncommit the line.
Commits are a special type of line in many languages that allow us humans to stick info (generally for humans) inside the code that the interpreter skips over. From the machines perspective this block looks like:
environment:
POSTGRES_PASSWORD: HDFnWzVZ5bGI
Note that the entire line is missing.
As a side note. Please change the password as it's been posted to the Internet.
+1. We are a household of sysadmins/engineers. Sure I or my wife could design a PC for media in an afternoon - but I don't want to deal with it.
An apple TV was a no fuss, no headache media box that can interface with the servers that store my media.