In emberjs/data#1859 DS._setupContainer was
introduced to Ember-Data. This allows moduleForModel to use an
isolatedContainer with all the trimmings of Ember-Data instead of only
the store, including default serializers and adapters.

Example usage might read like:

    var App = Ember.Application.create();
    App.ApplicationAdapter = DS.RESTAdapter.extend();
    App.WhapModel = DS.Model.extend();

    moduleForModel('whap', { needs: ['adapter:application'] });

Ember-Data will now discover the application adapter with its regular
application semantics.

In Ember-Data installations pre-DS._setupContainer, the old behaviors
(for better or worse, mostly worse) are unchanged.

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