Per this change, `backbone_rails_sync.js` should change this:

```
var success = options.success;
    params.success = function(resp) {
      if (success) success(model, resp, options);
      model.trigger('sync', model, resp, options);
    };
```

to this:

```
var success = options.success;
    params.success = function(resp) {
      if (success) success(resp);
      model.trigger('sync', model, resp, options);
    };
```