[heroku] 'heroku' does not appear to be a git repository

Following official Heroku article:

Initialize GIT

$ cd myapp
$ git init

$ git add .
$ git commit -m "my first commit"

Then create (initialize) heroku app with:

$ heroku create YourAppName

Lastly add git remote:

$ heroku git:remote -a YourAppName

Now you can safely deploy your app with:

$ git push heroku master

You should wait for some time and see if you don't get any error/interrupt on console while deploying. For details look at heroku article.