Why this code works differently in Heroku?

Why this code works differently in Heroku?

References

Reference NO 1

https://devcenter.heroku.com/articles/multiple-environments

Reference NO 2

https://devcenter.heroku.com/articles/git

Reference NO 3

http://stackoverflow.com/questions/13644451/why-this-code-works-differently-in-heroku

Reference NO 4

http://stackoverflow.com/questions/2971550/how-to-push-different-local-git-branches-to-heroku-master

Reference NO 5

http://stackoverflow.com/questions/4269922/permission-denied-publickey-when-deploying-heroku-code-fatal-the-remote-end

Reference NO 6

http://guides.railsgirls.com/heroku/

Reference NO 7

http://jayunit100.blogspot.com/2012/05/how-git-heroku-and-your-laptop-work.html

Reference NO 8

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