Fix allowing kue app to be hosted as child of another parent express app

With this added slash in the base path redirect, the kue app performs correct redirects if it is hosted as part of a parent express app, on its own dedicated path, like so:

```js
var app = require('express')(); // parent express app
app.use('/kueapp', require('kue').app); // we want the kue UI to be available on the 'kueapp' subpath
app.listen(1337); // the kue app is now available on http://localhost:1337/kueapp
```

This fixes the current failing behavior, as a redirect without the slash sends the user to http://localhost:1337/kueappactive, which returns 404.