EmberData include [RESOLVED]

I have the following in my model hook:

return this.store.findRecord('book', id, { include: 'authors' });

and I was expecting that in my template, the following will work:

{{model.author.last}}, {{model.author.first}}

nothing appears in my template for those fields

Can you add the route and model definitions for those?

My hunch is that adding async: false to the relationship definition will solve this?

Though, the include is plural, and the relationship is singular?

@NullVoxPopuli, it turns out after hours of debugging that my jsonapi backend was having problems with serializing the links in the data it returns resulting in problems with resolving the related domains.