emberjs/data — pull request #1105 by kevinwon1985 (2013-07-31 09:21:32+00:00)
Title: get primaryKey from mappings

In DS.Serializer @desc
```javascript
App.Adapter.map('App.Person', {
primaryKey: '_id'
});
```
but in DS.Serializer#_primaryKey, use DS.Serializer#configurationForType to get primaryKey mapping