Add Dockerfile

This allows to run the blog application within a docker container.

Dockerfile

@@ -0,0 +1,19 @@
+FROM ruby:latest
+
+# Create and switch to a user called app
+RUN useradd --create-home --shell /bin/bash blog
+
+WORKDIR /home/blog
+
+# copy gemfile separately to cache step before more frequent code changes :)
+COPY Gemfile Gemfile.lock /home/blog/
+RUN bundle install
+
+ADD . /home/blog
+RUN chown --recursive blog:blog /home/blog
+
+USER blog
+
+EXPOSE 4567
+
+ENTRYPOINT ["bundle","exec"]

README.md

@@ -9,16 +9,52 @@ Have a look at this blog hosted on Heroku: https://google-doc-blog.herokuapp.com
 * You need a running `ruby` installation >= version 2.3
 * Make sure to have the `bundler` gem installed
 
-## Usage
+, or
+
+* You need a running docker installation >= version 19.3
+
+## Usage (local)
 
 1. Run `bundle install` to install all required dependencies
 1. Run `bundle exec ruby bin/setup.rb` and follow the instructions to set up your environment
 1. Execute `bundle exec rackup -p 4567 config.ru` to start the server
 1. You should be able to open the webapp via `http://localhost:4567` in your browser 
 
+## Usage (docker)
+
+First, build the image 
+```
+docker build --tag google-doc-blog:latest ./
+```
+
+Then, run the setup script in a container
+```
+docker run --rm \
+           --interactive \
+           --volume $PWD/config:/home/blog/config \
+       google-doc-blog:latest \
+       ruby bin/setup.rb
+```
+
+Finally, start the web server in a container
+```
+docker run --rm \
+           --publish 4567:4567 \
+           --volume $PWD:/home/blog \
+       google-doc-blog:latest \
+       rackup --port 4567 --host 0.0.0.0 config.ru
+```
+
 ## Running the tests
 
 Execute `bundle exec rspec` to run the entire test suite.
+With docker, run
+```
+docker run --rm \
+           --volume $PWD:/home/blog \
+           google-doc-blog:latest \
+           rspec
+```
 
 ## Built With
 

bin/setup.rb

@@ -3,6 +3,9 @@
 require_relative '../app/config'
 require_relative '../app/google_drive_connector'
 
+# Don't buffer the output to avoid broken IO in docker container...
+$stdout.sync = true
+
 puts 'This script will guide you through the required setup steps setup the '\
      'blog. Please follow these steps:'