added production url to readme
Added git duet to the gemfile

Signed-off-by: Evan Tedesco <evantedesco@gmail.com>
[#68385464] User can see the input form and the shorten button on the home page

Signed-off-by: Evan Tedesco <evantedesco@gmail.com>
[#68385466] User can shorten URL and see both original and shortened URL on one page

Signed-off-by: Evan Tedesco <evantedesco@gmail.com>