How does Ember make the decision about what URL to look at when requesting data?

I have the following route file index.js:

export default Ember.Route.extend({
  model() {
    return this.store.findAll('rental');
  }
});

In the tutorial on the Ember site, it states that Ember will then fetch data from /rentals url - why does it not look at /rental (as I had defined in the route file)?