docs: function defineApp(app) {
  
      app.use('/foo', function appFoo(req, res) {
          if (req.xhr) {
              var body = {
                  foo: 'bar'
              };
              responseSender.sendJSON(res, body);
          } else {
              responseSender.sendPage(res, 'Foo', '<h1>Bar!</h1>', 200);
          }
      });
  
      app.use('/fail', function appFail(req, res) {
          /* jshint unused: false, quotmark: false */
          throw new Error("Don't worry, the error handler will take care of this");
      });
  
      app.use('/fail-async', function appFailAsync(req, res) {
          /* jshint unused: false, quotmark: false */
          setTimeout(function() {
              throw new Error("I may be async, but the error handler will still catch me!");
          }, 100);
      });
  
  
      app.use('/', express.static(__dirname));
  
  }