EMBER AUTH 404 POST http://localhost:3000/users/sign_in 401 (Unauthorized)

I have found series of good tutorials for auth.I have implemented them.And they almost perfectly good to go except one little problem.I have got the error in title.I have followed along with this http://ift.tt/1iWJyyD so you can have an idea how the code looks like.In rails part not much going on.Added active_model_serializer and rack-cors.Configured a json_api.rb.That's it.

Weird Part isenter image description here

here is the repo.please help me on this matter