[test] rails-hello-web

[docker-library-bot]

Create a simple hello-world web application to ensure that rails can run and display a page. Start the web server container with the code in the background (be sure to give it a unique name), wait a reasonable amout of time for it the web service to be ready for connections, curl service to ensure that the "hello world/web" page is showing. Be sure to clean up the container at the end or if there is an error.

[tianon]

The rails image is now deprecated (docker-library/docs#503), and thus writing tests for it would be wasted effort.