nextcloud-docs/rails/content.md

What is Ruby on Rails?

Ruby on Rails or, simply, Rails is an open source web application framework which runs on the Ruby programming language. It is a full-stack framework. This means that "out of the box", Rails can create pages and applications that gather information from a web server, talk to or query a database, and render templates. As a result, Rails features a routing system that is independent of the web server.

wikipedia.org/wiki/Ruby_on_Rails

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How to use this image

Create a Dockerfile in your Rails app project

FROM rails:onbuild

Put this file in the root of your app, next to the Gemfile.

This image includes multiple ONBUILD triggers which should cover most applications. The build will COPY . /usr/src/app, RUN bundle install, EXPOSE 3000, and set the default command to rails server.

You can then build and run the Docker image:

$ docker build -t my-rails-app .
$ docker run --name some-rails-app -d my-rails-app

You can test it by visiting http://container-ip:3000 in a browser or, if you need access outside the host, on port 8080:

$ docker run --name some-rails-app -p 8080:3000 -d my-rails-app

You can then go to http://localhost:8080 or http://host-ip:8080 in a browser.

Generate a Gemfile.lock

The onbuild tag expects a Gemfile.lock in your app directory. This docker run will help you generate one. Run it in the root of your app, next to the Gemfile:

$ docker run --rm -v "$PWD":/usr/src/app -w /usr/src/app ruby:2.1 bundle install

Bootstrap a new Rails application

If you want to generate the scaffolding for a new Rails project, you can do the following:

$ docker run -it --rm --user "$(id -u):$(id -g)" -v "$PWD":/usr/src/app -w /usr/src/app rails rails new --skip-bundle webapp

This will create a sub-directory named webapp inside your current directory.