ember associated records in template

I'm experimenting with ember and ember-localstorage-adapter and, in particular, I am trying to show properties of associated record in a template. I managed to build a jsbin (it needs to be run in a separate window by clicking the popup button of the result panel).

First run is ok (it shows the players for any purchases) but if the page is reloaded (apart from showing an error in console which I don't understand) old associated players disappear.

Manually remove the localstorage record with the key taster to retry:

What is the correct way to load not only main records associated with the current route (purchases) along with associated records (player) in order to use expression like {{item.player.name}} in template?