Dynamically load routes with express.js

I am using express.js as a webserver and would like an easy way to separate all the "app.get" and "app.post" functions to separate files. For example, if I would like to specify get and post functions for a login page, I would like to have a login.js file in a routes folder that is dynamically loaded (will automatically add all of the files without having to specify each one) when I run node app.j