Support composer server logs mysql as alias for db

[kadamwhite]

Today I tried to run composer server logs mysql, and was informed

No such service: mysql

I naïvely assumed this meant mysql logs just weren't available, and proceeded to debug the issue I was working on unsuccessfully through other means. It wasn't until later that I realized that the logs command wanted db, not mysql. This is a bit counter-intuitive since the other values are technology-specific, e.g. php and nginx.

I'd like to propose adding mysql as an alias for db so that either will show the desired logs.