album.js

app.factory('AlbumFactory', function(DS){
  var AlbumFactory = DS.defineResource({
    basePath: 'api',
    name: 'albums',  
    idAttribute: '_id',  
    // like the mongoose methods object, 
    //this object allows us to add 
    // functionality to the prototype
    // i.e. create instance methods
    methods: {
      raw: function(){
        return 'api/albums/'+ this._id + '.image'
      }
    }
  })
  return AlbumFactory; 
})
.controller('AlbumController', function(AlbumFactory){
  AlbumFactory.find('435')
  .then(function(album){
    // rawUrl = 'api/albums/435.image'
    var rawUrl = album.raw();
    // change the album
    album.name = 'newName';
    // save the changes to DB
    return album.DSUpdate();   
  })
  .then(function(updated){
    updated.name = 'newName'
  })
})