Change filename of Bower dependencies

Ive got an Ember app and want to use external libraries (like in my case gamps api). So Ive put a dependency in my bower.json file which looks like that:

"dependencies": {
    ...
    "gmaps-with-token": "http://ift.tt/1iglHJA",
    ...
}

Unfortunately bower install will load a file called 'index' without any suffix. However importing that file in my ember-cli-app with app.import(app.bowerDirectory + 'gmpas-width-token/index'); wont work and I dont know why. When I try to start the ember server, ember promps

"You must pass a file to 'app.import'. ..."

Can anybody explain me why this is a problem? Maybe its matters because of the missing file-suffix at the "index" file.