My original "load belongsTo association" failed without `{async: true}`, but I couldn't get anything to save to localStorage with `{async: true}` so I tried removing it. I got the load test to pass with [this change](https://github.com/carnesmedia/ember-localstorage-adapter/commit/7a53de9062b4c6595683cbe7bf16dfce96369db1#diff-38dcab2adf8a7e3431829d8daca050fcR270), but I still can't get the save test to work (more specifics there).

I've read that `{async: true}` is necessary for `hasMany` relationships in `LSAdapter`, but what is the preferred for `belongsTo`?