Best way to store DB config in Node.Js / Express app

What would be the best way to store DB config (username, password) in an open source app that runs on node.js / Express? Two specific questions:

1. Shall I put it into a separate config.js file in /lib folder, for example, and never include it into the master repository that is publicly available on GitHub?

2. To inlcude the config, is it as simple as require('./config.js') from the file that needs it or is there a better way of doing it?

PS sorry if the questions seem a bit simple or not so well formulated, but I'm just starting :)