Cannot get MEAN app deployed to Heroku because of “failed to detect app matching no buildpack”

I am trying to deploy a MEAN app to Heroku, but cannot push due to the following error:

Failed to detect app matching https://codon-buildpacks.s3.amazonaws.com/buildpacks/heroku/nodejs.tgz buildpack

I've already set my buildpack with:

heroku buildpacks:set heroku/nodejs

This is my first deployment to Heroku, so I'm brand new at this.

via universesurfer