So I came across ember-cli-bourbon, and have bourbon install in my app within 2 mins, awesome!
But how is this different than install bourbon with bower and import it in brocfile. Making libraries into addon seems a little overkill to me.
Even ember-cli-bourdon, which is a very thin & simple addon, does something which most users would fumble over.
I also think your question is answered by a post that is currently right under yours, How can I add Bootstrap to my ember-cli app?