Node.js - single app code, multiple runs with custom settings

I'm going to start software as service app in Node.js. Is there any way to have one source code and many app instances? I wanna develop and commit just one repo, that changes will be visible in all of app instances? Of course user can set own config like database and vhost. User files will be stored in his file system directory mounted to the vhost. Where will be his /her public files as images or download added from CMS.

Best, Mark.