If you read the answers in the link below, you will understand how to download and save files on the server using emberjs:
Download Ember Data File
In the answer provided by "Toran Billups" in the link above, the lines below, which I copied from his answer, save to the server:
var person = PersonApp.Person.createRecord({username: 'heyo', attachment: fileToUpload});
self.get('controller.target').get('store').commit()
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