add local testing section to readme

README.md

@@ -95,6 +95,39 @@ class { '::postgres_hardening':
 }
 ```
 
+## Local Testing
+
+For local testing you can use vagrant and Virtualbox of VMWare to run tests locally. You will have to install Virtualbox and Vagrant on your system. See [Vagrant Downloads](http://downloads.vagrantup.com/) for a vagrant package suitable for your system. For all our tests we use `test-kitchen`. If you are not familiar with `test-kitchen` please have a look at [their guide](http://kitchen.ci/docs/getting-started).
+
+Next install test-kitchen:
+
+```bash
+# Install dependencies
+gem install bundler
+bundle install
+
+# Fetch tests
+bundle exec thor kitchen:fetch-remote-tests
+
+# Do lint checks
+bundle exec rake lint
+
+# Do spec checks
+bundle exec rake spec
+
+# fast test on one machine
+bundle exec kitchen test default-ubuntu-1204
+
+# test on Debian-based machines
+bundle exec kitchen test
+
+# for development
+bundle exec kitchen create default-ubuntu-1204
+bundle exec kitchen converge default-ubuntu-1204
+```
+
+For more information see [test-kitchen](http://kitchen.ci/docs/getting-started)
+
 ## Contributors + Kudos
 
 * Edmund Haselwanter [ehaselwanter](https://github.com/ehaselwanter)