code: function (store, type, fixtureRecord) {
      var fixture;
      if (fixtureRecord.id) {
        type = this._parseModelOrType(store, type);
        // lookup for a fixture
        fixture = this.fixtureForId(store, type, fixtureRecord.id);
        if (fixture) {
          Ember.merge(fixture, fixtureRecord);
          this._touchDateAttr(store, type, fixture, 'updatedAt');
          return fixture;
        }
      }
      else {
        throw new Error('Updating a fixture requires an ID.');
      }
      // new fixture
      this._touchDateAttr(store, type, fixtureRecord, 'createdAt', 'updatedAt');
      this.fixturesForType(store, type).pushObject(fixtureRecord);
      return fixtureRecord;
    }
docs: Update the fixture for given type and fixture record
  
  @method updateFixtures
  @param {DS.Store} store
  @param {DS.Model|string} type
  @param {Object} fixtureRecord
  @return {Object}