Rails app deploy on Heroku -

i'm new in rails app development little bit confusing rails deployment.

i following guide below , done @ all. mean rails app on production mode?

need change puma rack_env 'production' in profile before pushing heroku?

https://devcenter.heroku.com/articles/getting-started-with-rails4

i believe so. entire tutorial setting rails server work in production mode. using inductive logic, seems tutorial assuming you're in production:

"rails 4 no longer has static index page in production. when you’re using new app, there not root page in production, need create one. first create controller called welcome our home page live:"

indicates me it's assuming rails server running in production.

to make doubly sure, can check heroku logs , line says:

rails [your version] application starting in production