`shippingRates` is not a property of `zone`, you should move it one level up

```coffeescript
zoneRates: [{
  zone:
    typeId: 'zone'
    id: zone.id
  shippingRates: [{
    ...
  }]
}]
```

http://commercetools.de/dev/http-api-projects-shippingMethods.html#zone-rate