Ember cli Managing dependencies for custom folders

I have an ember app, and a folder with a file playGame/game.js. This file includes game logic, and I want to import it for asset compilation.

If this file is under app/playGame/game.js and my Brocfile is like this:

app.import('app/playGame/game.js')

this gives the error, path or pattern app/playGame/game.js didn't match any files..

but if I put the file under bower_components/playGame/game.js and my Brocfile:

app.import('bower_components/playGame/game.js'), this compiles successfully.

What is the problem and solution here?