Ruby to docker (#181)

* Start of dockerfile with it installing dependecies from the gemspec file

* Docker container runs inspec_tools

* locally built and installed inspec_tools.gemspec and updated README.md

* Created multi-stage build dockerfile and updated README.md

* Updated README.md commands and changed apk add git-lfs in Dockerfile

* Changed --update to --no-cache

* updated Dockerfile and README.md

* Added the accepting of the chef_lisence into the Dockerfile and updated the commands on the README.md

* Combined Command line and Docker usage sections

* Fixed command inside README.md

* Update Docker execution instructions

* On Windows, only a single % is required around variables

Authored-by: John <atwoodj@mitre.org>

Author: jsa5593

Dockerfile

@@ -0,0 +1,24 @@
+FROM ruby:alpine AS builder
+
+RUN mkdir -p /share
+RUN apk add --no-cache build-base git-lfs
+
+COPY . /build
+RUN cd /build && \
+    bundle install && \
+    gem build inspec_tools.gemspec -o inspec_tools.gem
+
+
+FROM ruby:alpine
+
+ENV CHEF_LICENSE=accept
+RUN apk add --no-cache build-base
+
+COPY --from=builder /build/inspec_tools.gem /build/
+RUN gem install build/inspec_tools.gem
+    
+RUN apk del build-base
+
+ENTRYPOINT ["inspec_tools"]
+VOLUME ["/share"]
+WORKDIR /share

README.md

@@ -61,6 +61,13 @@ xccdf_results = tool.to_xccdf(attribs_json)
 On the Command Line, `inspec_tools help` will print a listing of all the command with a short description.
 For detailed help on any command, run `inspec_tools help [COMMAND]`. Help can also be called with the `-h, --help` flags after any command, like `inspec_tools xccdf2inspec -h`.
 
+For Docker usage, replace the `inspec_tools` command with the correct Docker command below for your operating system:
+
+ - **On Linux and Mac**: `docker run -it -v$(pwd):/share mitre/inspec_tools`
+ - **On Windows CMD**: `docker run -it -v%cd%:/share mitre/inspec_tools`
+ 
+Note that all of the above Docker commands will mount your current directory on the Docker container. Ensure that you have navigated to the directory you intend to convert files in before executing the command.
+
 ### generate_map
 
 This command will generate a `mapping.xml` file that can be passed in to the `csv2inspec` command with the `--m` option.