Select2 is passing an object literal into the handleCompanySelect method on the PeopleNewController.

app.js

App.PeopleNewController = Ember.ObjectController.extend({

    companySelection: null,

    actions: {
        doneEditing: function () {

            var person = this.get('model');

            person.save();
        },

        handleCompanySelect: function(company) {

            var companyId = Ember.get(company, 'id');

            this.store.find('company', companyId).then(function(company){

                var person = this.get('model');
                person.set('company', company);

                company.get('people').pushObject(person);
            });
        }
    }
});

company.js

App.Company = App.Taskable.extend({

    name: DS.attr('string'),

    people: DS.hasMany('person')
});

person.js

App.Person = App.Taskable.extend({

  firstName: DS.attr('string'),

  lastName: DS.attr('string'),

  city: DS.attr('string'),

  state: DS.attr('string'),

  email: DS.attr('string'),

  company: DS.belongsTo('company')
});