This is a very lightweight Docker image based on Ruby Alpine to run a Rails 5 application. I also provide a docker-compose file to run your project using a PostgreSQL database.

Clone the repository:

git clone [email protected]:pacuna/rails5-docker-alpine.git

Create a new Rails application under the repository directory

cd rails-docker-alpine
rails new . --database=postgresql

Modify your database configuration to use the postgresql container configuration:

default: &default
  adapter: postgresql
  encoding: unicode
  # For details on connection pooling, see rails configuration guide
  # http://guides.rubyonrails.org/configuring.html#database-pooling
  pool: <%= ENV.fetch("RAILS_MAX_THREADS") { 5 } %>
  host: db
  username: postgres

Build the project:

docker-compose build

Create the database and run the migrations:

docker-compose run --rm web bin/rails db:create
docker-compose run --rm web bin/rails db:migrate

Run the app:

docker-compose up -d

Visit your application at localhost:3000.

Tested with:

• Ruby 2.5.1p57 (2018-03-29 revision 63029) [x86_64-linux]
• Rails 5.2.2 (to create the new application)
• Docker version 18.09.0, build 4d60db4
• docker-compose version 1.23.1, build b02f1306