Add failing test for loading hasMany associations

This incorporates the proposed fix for pouchdb-community#16, but it doesn’t
actually fix the problem. Perhaps I’m misunderstanding!

addon/serializers/pouch.js

@@ -1,3 +1,5 @@
 import DS from 'ember-data';
 
-export default DS.RESTSerializer.extend({});
+export default DS.RESTSerializer.extend({
+  _shouldSerializeHasMany: function() { return true; }
+});

tests/dummy/app/models/food-item.js

@@ -5,5 +5,6 @@ import DS from 'ember-data';
 export default DS.Model.extend({
   rev: DS.attr('string'),
 
-  name: DS.attr('string')
+  name: DS.attr('string'),
+  soup: DS.belongsTo('taco-soup', { async: true })
 });

tests/integration/adapters/pouch-basics-test.js

@@ -114,6 +114,38 @@ test('create a new record', function (assert) {
   });
 });
 
+test('creating an associated record saves it in the parent', function (assert) {
+  assert.expect(1);
+
+  var done = assert.async();
+  Ember.RSVP.Promise.resolve().then(() => {
+    return this.db().bulkDocs([
+      { _id: 'tacoSoup_2_C', data: { flavor: 'al pastor', ingredients: [] } }
+    ]);
+  }).then(() => {
+    return this.store().findRecord('taco-soup', 'C');
+  }).then(tacoSoup => {
+    var newIngredient = this.store().createRecord('food-item', {
+      name: 'pineapple'
+    });
+
+    return Ember.RSVP.all([newIngredient.save().then(ingredient => ingredient), tacoSoup]);
+  }).then(([ingredient, tacoSoup]) => {
+    tacoSoup.get('ingredients').pushObject(ingredient);
+    return tacoSoup.save();
+  }).then(() => {
+    this.store().unloadAll();
+
+    return this.store().findRecord('taco-soup', 'C');
+  }).then(tacoSoup => {
+    return tacoSoup.get('ingredients');
+  }).then(foundIngredients => {
+    assert.deepEqual(foundIngredients.mapBy('name'), ['pineapple'],
+      'should have fully loaded the associated items');
+    done();
+  });
+});
+
 // This test fails due to a bug in ember data
 // (https://github.com/emberjs/data/issues/3736)
 // starting with ED v2.0.0-beta.1. It works again with ED v2.1.0.