Padrino is an open source web application framework which runs via the Ruby programming language. It is a full-stack framework: it allows creating pages and applications that gather information from the web server, talk to or query the database, and render templates out of the box. As a result, Padrino features a routing system that is independent of the web server.
FROM padrino:onbuild
Put this file in the root of your app, next to the Gemfile.
This image includes multiple ONBUILD triggers so that should be all that you need for most applications. The build will ADD . /usr/src/app, RUN bundle install, EXPOSE 3000, and set the default command to padrino start.
Then build and run the docker image.
docker build -t my-padrino-app .
docker run --name some-padrino-app -d my-padrino-app
Test it by visiting http://container-ip:3000 in a browser. On the other hand, if you need access outside the host on port 8080:
docker run --name some-padrino-app -p 8080:3000 -d my-padrino-app
Then hit http://localhost:8080 or http://host-ip:8080 in a browser.