title: Docker Compose Could not locate Gemfile or .bundle/ directory
body: <p>When I run <code>docker-compose up -d</code> I get the following error:</p>
  
  <p><code>web_1  | Could not locate Gemfile or .bundle/ directory</code> </p>
  
  <p>However the image is being created. I want to have a Rails application, and for the Docker files to live outside the rails application. I have the following <code>Dockerfile</code></p>
  
  <pre><code>FROM ruby:2.5
  RUN apt-get update -qq &amp;&amp; apt-get install -y build-essential libpq-dev nodejs
  
  WORKDIR /app
  
  COPY ./app/Gemfile Gemfile
  
  # Install Gems
  RUN bundle install
  ADD . /app
  </code></pre>
  
  <p>In the <code>docker-compose.yml</code> file I have the Following configuration:</p>
  
  <pre><code>version: '3'
  services:
    db:
      image: postgres:9.6.1 # To Edit - Default is postgresql.
    web:
      build: .
      command: bundle exec rails s -p 3000 -b '0.0.0.0'
      volumes:
        - .:/app
      ports:
        - "3000:3000"
      depends_on:
        - db
  </code></pre>
  
  <p>And for the Gemfile I have the following code:</p>
  
  <pre><code>source 'https://rubygems.org'
  git_source(:github) { |repo| "https://github.com/#{repo}.git" }
  
  ruby '2.5.1'
  
  # Bundle edge Rails instead: gem 'rails', github: 'rails/rails'
  gem 'rails', '~&gt; 5.2.0'
  # Use postgresql as the database for Active Record
  gem 'pg'
  # Use Puma as the app server
  gem 'puma', '~&gt; 3.11'
  # Use SCSS for stylesheets
  gem 'sass-rails', '~&gt; 5.0'
  # Use Uglifier as compressor for JavaScript assets
  gem 'uglifier', '&gt;= 1.3.0'
  # See https://github.com/rails/execjs#readme for more supported runtimes
  # gem 'mini_racer', platforms: :ruby
  
  # Use CoffeeScript for .coffee assets and views
  gem 'coffee-rails', '~&gt; 4.2'
  # Turbolinks makes navigating your web application faster. Read more: https://github.com/turbolinks/turbolinks
  gem 'turbolinks', '~&gt; 5'
  # Build JSON APIs with ease. Read more: https://github.com/rails/jbuilder
  gem 'jbuilder', '~&gt; 2.5'
  # Use Redis adapter to run Action Cable in production
  # gem 'redis', '~&gt; 4.0'
  # Use ActiveModel has_secure_password
  # gem 'bcrypt', '~&gt; 3.1.7'
  
  # Use ActiveStorage variant
  # gem 'mini_magick', '~&gt; 4.8'
  
  # Use Capistrano for deployment
  # gem 'capistrano-rails', group: :development
  
  # Reduces boot times through caching; required in config/boot.rb
  gem 'bootsnap', '&gt;= 1.1.0', require: false
  
  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]
  end
  
  group :development do
    # Access an interactive console on exception pages or by calling 'console' anywhere in the code.
    gem 'web-console', '&gt;= 3.3.0'
    gem 'listen', '&gt;= 3.0.5', '&lt; 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', '~&gt; 2.0.0'
  end
  
  group :test do
    # Adds support for Capybara system testing and selenium driver
    gem 'capybara', '&gt;= 2.15', '&lt; 4.0'
    gem 'selenium-webdriver'
    # Easy installation and use of chromedriver to run system tests with Chrome
    gem 'chromedriver-helper'
  end
  
  # Windows does not include zoneinfo files, so bundle the tzinfo-data gem
  gem 'tzinfo-data', platforms: [:mingw, :mswin, :x64_mingw, :jruby]
  </code></pre>
  
  <p>I'm not sure if it has something to do with the Rails or Ruby version. I also see that the Gemfile is there once I go into the container and run <code>ls</code> so is not that theres no Gemfile.</p>
  
  <p><code>root@ab38d643df47:/app# ls
  Dockerfile  Gemfile  Gemfile.lock  README.md  app  docker-compose.yml
  </code></p>