Docker support for rails-api app

docker-compose.yml

version: "3"
services:
  api:
    build: .
    command: sh -c "rm -rf /api/tmp/pids/server.pid; rails s -b 0.0.0.0"
    environment:
      # database configuration for development
      DEVELOPMENT_DATABASE_URL: postgres://postgres:mellon@postgres:5432/api_dev
      # database configuration for testing
      TEST_DATABASE_URL: postgres://postgres:mellon@postgres:5432/api_test
      # database configuration for production
      DATABASE_URL:
      # Turning off warnings when running Rails with Ruby 2.7
      # https://stackoverflow.com/a/59594760
      RUBYOPT: '-W:no-deprecated -W:no-experimental'
    depends_on:
      - postgres
    volumes:
      - .:/api
    ports:
      - 3000:3000
  postgres:
    image: postgres:11-alpine
    environment:
      POSTGRES_USER: postgres
      POSTGRES_PASSWORD: mellon
    ports:
      - 5432:5432

Dockerfile

# docker run --rm -v "$(pwd):/api" -ti -w /api ruby:2.7-alpine sh
FROM ruby:2.7-alpine

EXPOSE 3000

RUN apk --no-cache add alpine-sdk postgresql-dev tzdata
RUN mkdir /api

WORKDIR /api

COPY Gemfile /api/Gemfile
COPY Gemfile.lock /api/Gemfile.lock
RUN bundle install

COPY . /api

CMD [ "rails", "s", "-b", "0.0.0.0" ]

Gemfile

source 'https://rubygems.org'
git_source(:github) { |repo| "https://github.com/#{repo}.git" }

ruby '2.7.0'

# Bundle edge Rails instead: gem 'rails', github: 'rails/rails'
gem 'rails', '~> 6.0.2', '>= 6.0.2.1'
# Use postgresql as the database for Active Record
gem 'pg', '>= 0.18', '< 2.0'
# Use Puma as the app server
gem 'puma', '~> 4.1'
# Build JSON APIs with ease. Read more: https://github.com/rails/jbuilder
# gem 'jbuilder', '~> 2.7'
# Use Redis adapter to run Action Cable in production
# gem 'redis', '~> 4.0'
# Use Active Model has_secure_password
# gem 'bcrypt', '~> 3.1.7'

# Use Active Storage variant
# gem 'image_processing', '~> 1.2'

# Reduces boot times through caching; required in config/boot.rb
gem 'bootsnap', '>= 1.4.2', require: false

# Use Rack CORS for handling Cross-Origin Resource Sharing (CORS), making cross-origin AJAX possible
gem 'rack-cors'

# Soft deletes for ActiveRecord done right
gem 'discard', '~> 1.1'

# Flexible authentication solution for Rails with Warden
gem 'devise', '~> 4.7', '>= 4.7.1'
# JWT authentication for devise with configurable token revocation strategies
gem 'devise-jwt', '~> 0.6.0'

group :development, :test do
  # Call 'byebug' anywhere in the code to stop execution and get a debugger console
  gem 'byebug', platforms: [:mri, :mingw, :x64_mingw]
  gem 'rspec-rails', '~> 3.9'
end

group :test do
  # Used to ensure a clean state for testing by cleaning the database
  gem 'database_cleaner'

  # Fixtures replacement with a straightforward definition syntax
  gem 'factory_bot_rails', '~> 5.1', '>= 5.1.1'

  # Fake data generator to use in tests
  gem 'faker', '~> 2.10', '>= 2.10.1'

  # Matchers for specs
  gem 'shoulda-matchers', '~> 4.2'

  # Test coverage report
  gem 'simplecov', require: false, group: :test
end

group :development do
  gem 'listen', '>= 3.0.5', '< 3.2'
  # Spring speeds up development by keeping your application running in the background. Read more: https://github.com/rails/spring
  gem 'spring'
  gem 'spring-watcher-listen', '~> 2.0.0'
end

# Windows does not include zoneinfo files, so bundle the tzinfo-data gem
gem 'tzinfo-data', platforms: [:mingw, :mswin, :x64_mingw, :jruby]

Gemfile.lock

GEM
  remote: https://rubygems.org/
  specs:
    actioncable (6.0.2.1)
      actionpack (= 6.0.2.1)
      nio4r (~> 2.0)
      websocket-driver (>= 0.6.1)
    actionmailbox (6.0.2.1)
      actionpack (= 6.0.2.1)
      activejob (= 6.0.2.1)
      activerecord (= 6.0.2.1)
      activestorage (= 6.0.2.1)
      activesupport (= 6.0.2.1)
      mail (>= 2.7.1)
    actionmailer (6.0.2.1)
      actionpack (= 6.0.2.1)
      actionview (= 6.0.2.1)
      activejob (= 6.0.2.1)
      mail (~> 2.5, >= 2.5.4)
      rails-dom-testing (~> 2.0)
    actionpack (6.0.2.1)
      actionview (= 6.0.2.1)
      activesupport (= 6.0.2.1)
      rack (~> 2.0, >= 2.0.8)
      rack-test (>= 0.6.3)
      rails-dom-testing (~> 2.0)
      rails-html-sanitizer (~> 1.0, >= 1.2.0)
    actiontext (6.0.2.1)
      actionpack (= 6.0.2.1)
      activerecord (= 6.0.2.1)
      activestorage (= 6.0.2.1)
      activesupport (= 6.0.2.1)
      nokogiri (>= 1.8.5)
    actionview (6.0.2.1)
      activesupport (= 6.0.2.1)
      builder (~> 3.1)
      erubi (~> 1.4)
      rails-dom-testing (~> 2.0)
      rails-html-sanitizer (~> 1.1, >= 1.2.0)
    activejob (6.0.2.1)
      activesupport (= 6.0.2.1)
      globalid (>= 0.3.6)
    activemodel (6.0.2.1)
      activesupport (= 6.0.2.1)
    activerecord (6.0.2.1)
      activemodel (= 6.0.2.1)
      activesupport (= 6.0.2.1)
    activestorage (6.0.2.1)
      actionpack (= 6.0.2.1)
      activejob (= 6.0.2.1)
      activerecord (= 6.0.2.1)
      marcel (~> 0.3.1)
    activesupport (6.0.2.1)
      concurrent-ruby (~> 1.0, >= 1.0.2)
      i18n (>= 0.7, < 2)
      minitest (~> 5.1)
      tzinfo (~> 1.1)
      zeitwerk (~> 2.2)
    bcrypt (3.1.13)
    bootsnap (1.4.5)
      msgpack (~> 1.0)
    builder (3.2.4)
    byebug (11.0.1)
    concurrent-ruby (1.1.5)
    crass (1.0.6)
    database_cleaner (1.7.0)
    devise (4.7.1)
      bcrypt (~> 3.0)
      orm_adapter (~> 0.1)
      railties (>= 4.1.0)
      responders
      warden (~> 1.2.3)
    devise-jwt (0.6.0)
      devise (~> 4.0)
      warden-jwt_auth (~> 0.4)
    diff-lcs (1.3)
    discard (1.1.0)
      activerecord (>= 4.2, < 7)
    docile (1.3.2)
    dry-auto_inject (0.7.0)
      dry-container (>= 0.3.4)
    dry-configurable (0.9.0)
      concurrent-ruby (~> 1.0)
      dry-core (~> 0.4, >= 0.4.7)
    dry-container (0.7.2)
      concurrent-ruby (~> 1.0)
      dry-configurable (~> 0.1, >= 0.1.3)
    dry-core (0.4.9)
      concurrent-ruby (~> 1.0)
    erubi (1.9.0)
    factory_bot (5.1.1)
      activesupport (>= 4.2.0)
    factory_bot_rails (5.1.1)
      factory_bot (~> 5.1.0)
      railties (>= 4.2.0)
    faker (2.10.1)
      i18n (>= 1.6, < 2)
    ffi (1.12.1)
    globalid (0.4.2)
      activesupport (>= 4.2.0)
    i18n (1.8.2)
      concurrent-ruby (~> 1.0)
    json (2.3.0)
    jwt (2.2.1)
    listen (3.1.5)
      rb-fsevent (~> 0.9, >= 0.9.4)
      rb-inotify (~> 0.9, >= 0.9.7)
      ruby_dep (~> 1.2)
    loofah (2.4.0)
      crass (~> 1.0.2)
      nokogiri (>= 1.5.9)
    mail (2.7.1)
      mini_mime (>= 0.1.1)
    marcel (0.3.3)
      mimemagic (~> 0.3.2)
    method_source (0.9.2)
    mimemagic (0.3.3)
    mini_mime (1.0.2)
    mini_portile2 (2.4.0)
    minitest (5.14.0)
    msgpack (1.3.1)
    nio4r (2.5.2)
    nokogiri (1.10.7)
      mini_portile2 (~> 2.4.0)
    orm_adapter (0.5.0)
    pg (1.2.2)
    puma (4.3.1)
      nio4r (~> 2.0)
    rack (2.1.1)
    rack-cors (1.1.1)
      rack (>= 2.0.0)
    rack-test (1.1.0)
      rack (>= 1.0, < 3)
    rails (6.0.2.1)
      actioncable (= 6.0.2.1)
      actionmailbox (= 6.0.2.1)
      actionmailer (= 6.0.2.1)
      actionpack (= 6.0.2.1)
      actiontext (= 6.0.2.1)
      actionview (= 6.0.2.1)
      activejob (= 6.0.2.1)
      activemodel (= 6.0.2.1)
      activerecord (= 6.0.2.1)
      activestorage (= 6.0.2.1)
      activesupport (= 6.0.2.1)
      bundler (>= 1.3.0)
      railties (= 6.0.2.1)
      sprockets-rails (>= 2.0.0)
    rails-dom-testing (2.0.3)
      activesupport (>= 4.2.0)
      nokogiri (>= 1.6)
    rails-html-sanitizer (1.3.0)
      loofah (~> 2.3)
    railties (6.0.2.1)
      actionpack (= 6.0.2.1)
      activesupport (= 6.0.2.1)
      method_source
      rake (>= 0.8.7)
      thor (>= 0.20.3, < 2.0)
    rake (13.0.1)
    rb-fsevent (0.10.3)
    rb-inotify (0.10.1)
      ffi (~> 1.0)
    responders (3.0.0)
      actionpack (>= 5.0)
      railties (>= 5.0)
    rspec-core (3.9.1)
      rspec-support (~> 3.9.1)
    rspec-expectations (3.9.0)
      diff-lcs (>= 1.2.0, < 2.0)
      rspec-support (~> 3.9.0)
    rspec-mocks (3.9.1)
      diff-lcs (>= 1.2.0, < 2.0)
      rspec-support (~> 3.9.0)
    rspec-rails (3.9.0)
      actionpack (>= 3.0)
      activesupport (>= 3.0)
      railties (>= 3.0)
      rspec-core (~> 3.9.0)
      rspec-expectations (~> 3.9.0)
      rspec-mocks (~> 3.9.0)
      rspec-support (~> 3.9.0)
    rspec-support (3.9.2)
    ruby_dep (1.5.0)
    shoulda-matchers (4.2.0)
      activesupport (>= 4.2.0)
    simplecov (0.17.1)
      docile (~> 1.1)
      json (>= 1.8, < 3)
      simplecov-html (~> 0.10.0)
    simplecov-html (0.10.2)
    spring (2.1.0)
    spring-watcher-listen (2.0.1)
      listen (>= 2.7, < 4.0)
      spring (>= 1.2, < 3.0)
    sprockets (4.0.0)
      concurrent-ruby (~> 1.0)
      rack (> 1, < 3)
    sprockets-rails (3.2.1)
      actionpack (>= 4.0)
      activesupport (>= 4.0)
      sprockets (>= 3.0.0)
    thor (1.0.1)
    thread_safe (0.3.6)
    tzinfo (1.2.6)
      thread_safe (~> 0.1)
    warden (1.2.8)
      rack (>= 2.0.6)
    warden-jwt_auth (0.4.0)
      dry-auto_inject (~> 0.6)
      dry-configurable (~> 0.8)
      jwt (~> 2.1)
      warden (~> 1.2)
    websocket-driver (0.7.1)
      websocket-extensions (>= 0.1.0)
    websocket-extensions (0.1.4)
    zeitwerk (2.2.2)

PLATFORMS
  ruby

DEPENDENCIES
  bootsnap (>= 1.4.2)
  byebug
  database_cleaner
  devise (~> 4.7, >= 4.7.1)
  devise-jwt (~> 0.6.0)
  discard (~> 1.1)
  factory_bot_rails (~> 5.1, >= 5.1.1)
  faker (~> 2.10, >= 2.10.1)
  listen (>= 3.0.5, < 3.2)
  pg (>= 0.18, < 2.0)
  puma (~> 4.1)
  rack-cors
  rails (~> 6.0.2, >= 6.0.2.1)
  rspec-rails (~> 3.9)
  shoulda-matchers (~> 4.2)
  simplecov
  spring
  spring-watcher-listen (~> 2.0.0)
  tzinfo-data

RUBY VERSION
   ruby 2.7.0p0

BUNDLED WITH
   2.1.2