-Getting Started on Heroku with Ruby | Heroku Dev Center
--https://devcenter.heroku.com/articles/getting-started-with-ruby
-Ruby Default Web Server | Heroku Dev Center
--https://devcenter.heroku.com/articles/ruby-default-web-server
-Deploying Rails Applications with the Puma Web Server | Heroku Dev Center
--https://devcenter.heroku.com/articles/deploying-rails-applications-with-the-puma-web-server
-Heroku
--http://www.nilab.info/wiki/Heroku.html