how to make changes in heroku app code example
Example 1: deploy to heroku
$ git add .
$ git commit -m "Added a Procfile."
$ heroku login
Enter your Heroku credentials.
...
$ heroku create <app-name>
Creating arcane-lowlands-8408... done, stack is cedar
$ git push heroku master
-----> Node.js app detected
...
-----> Launching... done
http://arcane-lowlands-8408.herokuapp.com deployed to Heroku
Example 2: set git remote heroku to https://git.heroku.com/resume-projects.git
$ heroku git:remote -a thawing-inlet-61413
set git remote heroku to https://git.heroku.com/thawing-inlet-61413.git