It's a simple NodeJS - Express server that returns a list of users from static data.
Clone the repo, perform an npm install inside the directory and run npm-start to get the server running. Dump a list of users as a JSON inside the export of users.js file in the data directory. The server just returns the JSON you place here so you can technically use this as a simple JSON returning server!
I do a lot of front-end development and many times the back-end APIs are just not ready for integration and testing. To get around that, I simply dump the mock JSON to this server and use it.