How to Link a Git Folder with an Existing Heroku App

1. Follow this guide to get Heroku setup on your command line tool of choice.
2. heroku git:remote -a project_name

where project name is the name of your Heroku app (if your app's URL is stellablog.herokuapp.com, project_name would be stellablog) and you're done! Your local Git folder will be linked with your Heroku app, and you can deploy your latest code to it.