Add docker config and instructions

Author: ChaseWiseman

.dockerignore

@@ -0,0 +1,2 @@
+build/
+.github/

Dockerfile

@@ -0,0 +1,20 @@
+FROM ruby:2.6-slim
+
+WORKDIR /srv/docs
+
+VOLUME /srv/docs/source
+EXPOSE 4567
+
+COPY . /srv/docs
+
+RUN apt-get update \
+    && apt-get install -y --no-install-recommends \
+        build-essential \
+        nodejs \
+    && gem install bundler \
+    && bundle install \
+    && apt-get remove -y build-essential \
+    && apt-get autoremove -y \
+    && rm -rf /var/lib/apt/lists/*
+
+CMD ["bundle", "exec", "middleman", "server", "--watcher-force-polling"]

README.md

@@ -15,15 +15,9 @@ You can contribute to this documentation by:
 
 > Please **do not submit feature requests or support requests for the REST API** here. You can use the [WooIdeas board](http://ideas.woocommerce.com/forums/133476-woocommerce?category_id=125014) or [Contact SkyVerge support](https://www.skyverge.com/support/).
 
-## Updating pages
-
-This project uses [Slate](https://github.com/lord/slate) for building the documentation pages.
+## Running locally
 
-Follow [Slate readme](https://github.com/lord/slate/blob/master/README.md) and [wiki](https://github.com/lord/slate/wiki) for instructions on how to edit files and make changes.
-
-## Deploying an update 
-
-To install locally use:
+### Vagrant
 
 ```shell
 bundle install
@@ -37,7 +31,33 @@ Then, to test changes locally run:
 bundle exec middleman server
 ```
 
-Finally, after pushing changes and you are ready to deploy use the script:
+### Docker
+
+1. Build the docker image:
+    ```shell
+    docker build . -t docs
+    ```
+1. Start the image:
+    ```shell
+    docker run -d --rm --name docs -p 4567:4567 -v $(pwd)/build:/srv/docs/build -v $(pwd)/source:/srv/docs/source docs
+    ```
+
+You will be able to access your site at http://localhost:4567.
+
+To build your sources while the container is running, run:
+```shell
+docker exec -it docs /bin/bash -c "bundle exec middleman build"
+```
+
+## Updating pages
+
+This project uses [Slate](https://github.com/lord/slate) for building the documentation pages.
+
+Follow [Slate readme](https://github.com/lord/slate/blob/master/README.md) and [wiki](https://github.com/lord/slate/wiki) for instructions on how to edit files and make changes.
+
+## Deploying an update 
+
+After pushing changes and you are ready to deploy use the script:
 
 ```shell
 bash deploy.sh