Js error on an ember app deployed to heroku

I received this when I loaded an ember app deployed to herocu: Error while processing route: rentals.index Unexpected token < in JSON at position 0 SyntaxError: Unexpected token < in JSON at position 0 at parse (<anonymous>)

Here is the ember app: (it works perfectly fine on my local) http://ift.tt/2kwIrew

This is the content of the app.json file { "name": "An ember tutorial app.", "description": "Simple", "repository": "http://ift.tt/2kwIrew", "keywords": ["ember", "node", "js"], "buildpacks": [ { "url": "http://ift.tt/2oiBVbe" } ], "env": { "GOOGLE_MAPS_API_KEY": { "description": "Google API KEY for Google Maps, http://ift.tt/1hIhfm2", "required": true } } }