current_user.js

Ember.Application.initializer({
  name: 'currentUser',

  initialize: function(container, application) {
    var user = App.User.create({});
    container.optionsForType('user', { instantiate: false, singleton: true });
    container.register('type:user', 'current', user);
  }
});

Ember.Application.initializer({
  name: 'injectCurrentUser',
  before: 'currentUser',

  initialize: function(container, application) {
    container.injection('controller:application', 'currentUser', 'user:current');
    container.typeInjection('route', 'currentUser', 'user:current');
  }
});