how to host in heroku and make ur app don't turn off code example
Example 1: how to stop a heroku app
$ heroku ps:scale web=0
Scaling web processes... done, now running 0
//once ready to go back online:
heroku ps:scale web=1
Example 2: turn off heroku app
From The Heroku Webpage
Dashboard => Your App Name => Resources => Pencil icon=> Flip the switch => Confirm