Enables a demo using Docker to be ran locally

This commit adds a Dockerfile and entrypoint in
the lib/demo folder, as well as useful documentation
in the README file.

This demo allows users to test out the latest version
of solidus using Docker locally. This setup is very
flexible and provides another option besides using
Heroku or manually installing everything.

README.md

@@ -66,6 +66,18 @@ Try out Solidus with one-click on Heroku:
 
 [![Deploy](https://www.herokucdn.com/deploy/button.svg)](https://heroku.com/deploy?template=https://github.com/solidusio/solidus)
 
+Alternatively, you can use Docker to run a demo on your local machine. Run the
+following command to download the image and run it at
+[http://localhost:3000](http://localhost:3000).
+
+```
+docker run --rm -it -p 3000:3000 solidusio/solidus-demo:latest
+```
+
+The admin interface can be accessed at
+[http://localhost:3000/admin/](http://localhost:3000/admin/), the default
+credentials are `admin@example.com` and `test123`.
+
 ## Getting started
 
 Begin by making sure you have

lib/demo/Dockerfile

@@ -0,0 +1,21 @@
+#
+# This image is intended to be used to test and demo Solidus
+# it is not intended for production purposes 
+#
+FROM ruby:2.5.1
+
+RUN curl -sL https://deb.nodesource.com/setup_10.x | bash -
+
+RUN apt-get update -qq && apt-get install -y build-essential libpq-dev nodejs
+
+RUN mkdir /solidus
+
+WORKDIR /solidus
+
+ADD . /solidus
+
+RUN bundle install
+
+RUN bundle exec rake sandbox
+
+CMD ["sh", "./lib/demo/docker-entrypoint.sh"]

lib/demo/README.md

@@ -0,0 +1,27 @@
+# Solidus Docker Demo
+The Dockerfile in this folder is intended for demoing purposes, meaning that a
+user can run an installation of Solidus using a Docker container.
+
+## How to build the image
+Make sure Docker is installed in your local and run the following command:
+
+```shell
+docker build -t solidusio/solidus-demo:latest -f lib/demo/Dockerfile .
+```
+
+## How to run the image
+You can either run the image you built locally or run the official image pushed
+in Dockerhub.
+
+```shell
+docker run --rm -it -p 3000:3000 solidusio/solidus-demo:latest
+```
+
+## How to push the image
+If you want to push the image you can use the following command, just note that
+this specific command will push the image to the official Solidus Dockerhub
+account.
+
+```shell
+docker push solidusio/solidus-demo:latest
+```

lib/demo/docker-entrypoint.sh

@@ -0,0 +1,6 @@
+#!/bin/bash
+
+export RAILS_ENV=development
+
+cd sandbox && \
+bundle exec rails s -p 3000 -b '0.0.0.0'