$git push heroku master のエラー

んーエラーが出る。

エラーはこれ。

Counting objects: 3, done.

Delta compression using up to 4 threads.

Compressing objects: 100% (3/3), done.

Writing objects: 100% (3/3), 514 bytes | 0 bytes/s, done.

Total 3 (delta 0), reused 0 (delta 0)

remote: Compressing source files... done.

remote: Building source:

remote:

remote:

remote:  !     Push rejected, no Cedar-supported app detected

remote: HINT: This occurs when Heroku cannot detect the buildpack

remote:       to use for this application automatically.

remote: See https://devcenter.heroku.com/articles/buildpacks

remote:

remote: Verifying deploy....

remote:

remote: ! Push rejected to fast-sierra-7291.

remote:

To https://git.heroku.com/fast-sierra-7291.git

! [remote rejected] master -> master (pre-receive hook declined)

error: failed to push some refs to 'https://git.heroku.com/fast-sierra-7291.git'

どうやって解決するべ。。。。