extractRelationship extractId is called without passing the relationship modelClass

[makepanic]

I don't know if it's expected behavior but we have access to the relationship modelClass so why not pass it to extractId?

https://github.com/201-created/ember-data-hal-9000/blob/master/addon/mixin.js#L205

[Ramblurr]

Yup, I had to override the mixin function manually to get this. Would be useful.