It's a reference to PG's essay titled "Ramen Profitable"[0]

[0] http://www.paulgraham.com/ramenprofitable.html

I believe ramen profitable means, it generates enough profit for the person to be able to subsist entirely on ramen.

To piggy back on another person...I'd say "ramen profitable"....means maybe something like 2-3k per month recurring income, with maybe 5-10 hours of maintenance required to run the application.