heroku add app to cli code example

Example 1: git push to heroku

$ git push heroku master

Example 2: heroku cli

$ sudo snap install --classic heroku

Example 3: heroku cli

$ brew tap heroku/brew && brew install heroku

Example 4: heroku and github on termi

$ git push heroku master
Initializing repository, done.
updating 'refs/heads/master'
...