Add support for EL8

* Added OEL to the metadata.json
* Added a very basic acceptance test to test the main components of the
  module. This should be expanded into multi-node tests later.
* Added a REFERENCE.md
* Updated the README.md to point to the REFERENCE.md and added
  instructions on how to run the acceptance test.

Closes voxpupuli#246

Gemfile

@@ -28,7 +28,7 @@ group :test do
   gem 'redcarpet',                                                  :require => false
   gem 'rubocop', '~> 0.49.1',                                       :require => false
   gem 'rubocop-rspec', '~> 1.15.0',                                 :require => false
-  gem 'mocha', '~> 1.4.0',                                          :require => false
+  gem 'mocha', '~> 1.10.0',                                         :require => false
   gem 'coveralls',                                                  :require => false
   gem 'simplecov-console',                                          :require => false
   gem 'parallel_tests',                                             :require => false
@@ -56,6 +56,7 @@ group :system_tests do
   gem 'serverspec',                         :require => false
   gem 'beaker-hostgenerator', '>= 1.1.22',  :require => false
   gem 'beaker-docker',                      :require => false
+  gem 'beaker-vagrant',                     :require => false
   gem 'beaker-puppet',                      :require => false
   gem 'beaker-puppet_install_helper',       :require => false
   gem 'beaker-module_install_helper',       :require => false

README.md

@@ -11,7 +11,7 @@
 
 ## Description
 
-This module manages firewalld, the userland interface that replaces iptables and ships with RHEL7.  The module manages firewalld itself as well as providing types and providers for managing firewalld zones, ports, and rich rules.
+This module manages firewalld, the userland interface that replaces iptables and ships with RHEL7+.  The module manages firewalld itself as well as providing types and providers for managing firewalld zones, ports, and rich rules.
 
 ## Compatibility
 
@@ -533,8 +533,28 @@ firewalld::direct_passthroughs:
 * `args`: Name of the passthroughhrough to add (e.g: -A OUTPUT -j OUTPUT_filter)
 
 
+## Testing
 
+### Unit Testing
 
+Unit tests can be executed by running the following commands:
+  * `bundle install`
+  * `bundle exec rake spec`
+
+### Acceptance Testing
+
+Acceptance tests are performed using [Beaker](https://github.com/puppetlabs/beaker) and require [Vagrant](https://vagrantup.com) and [VirtualBox](https://www.virtualbox.org) to run successfully.
+
+It is **HIGHLY RECOMMENDED** that you use the upstream Vagrant package and not one from your OS provider.
+
+To run the acceptance tests:
+  * `bundle install`
+  * `bundle exec rake beaker`
+
+To leave the Vagrant hosts running on failure for debugging:
+  * `BEAKER_destroy=onpass bundle exec rake beaker`
+  * `cd .vagrant/beaker_vagrant_files/default.yml`
+  * `vagrant ssh <host>`
 
 # Author