How to shutdown an app deployed on Heroku?
To completely 'stop' your app you can scale the web dynos down to zero which effectively takes all your app http-processes offline.
$ heroku ps:scale web=0Scaling web processes... done, now running 0
http://devcenter.heroku.com/articles/maintenance-mode
If you’re deploying a large migration or need to disable access to your application for some length of time, you can use Heroku’s built in maintenance mode. It will serve a static page to all visitors, while still allowing you to run rake tasks or console commands.
$ heroku maintenance:onMaintenance mode enabled.and later
$ heroku maintenance:offMaintenance mode disabled.
From the Heroku Web
Dashboard => Your App Name => Resources => Pencil icon=> Flip the switch => Confirm