How to dynamically load fixtures in ember.js - ember.js

Question

Hey I'm having trouble dynamically loading fixture data into my emberjs models. How should I go about doing this? The addArtist function at the bottom will add one song correctly but I'm not sure how to adapt this to loading all of the songs into the data store correctly. Is there an easier way than adding each one individually?
App.Store = DS.Store.extend({
revision: 13,
adapter: 'DS.FixtureAdapter'
});
App.Artist = DS.Model.extend({
name: DS.attr('string'),
tracks: DS.hasMany('App.Tracks')
});
App.Tracks = DS.Model.extend({
videoid: DS.attr('string'),
title: DS.attr('string'),
duration: DS.attr('number')
});
App.Artist.FIXTURES = [];
App.Tracks.FIXTURES = [];
App.loadFixtures = function(){
$.getJSON('/artists', function(data){
$.each(data.artists, function(i,v){
App.Artist.createRecord(v);
});
});
$.getJSON('/tracks', function(data){
$.each(data.tracks, function(i,v){
App.Tracks.createRecord(v);
});
});
};
App.addArtist = function(){
var artist = App.Artist.createRecord({
id: 3,
name: 'Justin Martin'
});
var track = App.Tracks.createRecord({
id: 300,
title: 'Jungle Mix',
duration: 200
});
artist.get('tracks').pushObject(track);
};
Sample JSON Responses:
{"artists":[
{"id":1,"name":"The (International) Noise Conspiracy","track_ids":[1,2,3,4]},
{"id":2,"name":"0SM","track_ids":[5]},
{"id":3,"name":"2am","track_ids":[6,7,8]}
]}
{"tracks":[
{"id":1,"videoid":"FyjmCg_VMU0","title":"Smash It Up","duration":197},
{"id":2,"videoid":"jKXWm9yi4DY","title":"Only Lovers Left Alive","duration":162},
{"id":3,"videoid":"fwbleH55CCk","title":"Up For Sale","duration":211},
{"id":4,"videoid":"50JdKhIB1EQ","title":"A New Morning, Changing Weather","duration":270},
{"id":5,"videoid":"bd6ve0ydHVo","title":"The Landing feat. Alex G - Original Mix","duration":322},
{"id":6,"videoid":"RnwVtbMW4x4","title":"Anxious","duration":238},
{"id":7,"videoid":"Yo0zsqa06ZE","title":"I Did Wrong","duration":305},
{"id":8,"videoid":"_9ydBAgg130","title":"I Love You (feat. Baekchan & Joohee)","duration":219}
]}
Should I include the track_ids in the Artists response or do they get added when I call this method?
artist.get('tracks').pushObject(track);