set model attribute from ember uploader S3 url? - ember.js

Question

I have got ember-uploader to upload files successfully to S3. When the image is done uploading, I would like to set the model property image_url to the returned URL, then preferably submit the form to create the record as well. How would I do that?
app/models/post.js:
import DS from 'ember-data';
export default DS.Model.extend({
name: DS.attr('string'),
body: DS.attr('string'),
image_url: DS.attr('string')
});
app/templates/posts/new.hbs:
<div class="new-post-form">
{{input type="text" placeholder="Name" value=name}}
{{input type="text" placeholder="Message" value=body}}
{{s3-upload value=image_url}}
<button {{action 'addPost'}} class="submit">Submit</button>
</div>
app/components/s3-upload.js:
import Ember from 'ember';
import EmberUploader from 'ember-uploader';
export default EmberUploader.FileField.extend({
url: 'http://localhost:3000/sign',
filesDidChange: (function() {
var uploadUrl = this.get('url');
var files = this.get('files');
var uploader = EmberUploader.S3Uploader.create({
url: uploadUrl
});
uploader.on('didUpload', function(response) {
// S3 will return XML with url
var uploadedUrl = Ember.$(response).find('Location')[0].textContent;
uploadedUrl = decodeURIComponent(uploadedUrl); // => http://yourbucket.s3.amazonaws.com/file.png
console.log("UPLOADED ! : " + uploadedUrl);
});
if (!Ember.isEmpty(files)) {
uploader.upload(files[0]); // Uploader will send a sign request then upload to S3 }
}).observes('files')
});
As you can see I tried setting the value of my s3-uploader component to image_url, that didn't seem to do anything.