var userController = require('./UserController');
app.route('/api/users')
  .get(userController.getUsers);

var userModel = require('./User');
function getUsers() {
  return JSON.parse(userModel);
}

var users = [];
users.push({id: "1", username: "regular", password: "user", role: "1"});
users.push({id: "2", username: "premium", password: "user", role: "2"});

undefined:1
[object Object],[object Object]
 ^

SyntaxError: Unexpected token o in JSON at position 1