Accessing nested mappings in a yam file (#1242)

* While working with mongod.conf file I spent hours trying to figure out how to access nested mappings.  When I read the code it used keys.shift to traverse the yaml object.  I tried changing to an array and voila I was able to access nested mappings.  I wanted to document my findngs and suggest an update to inspec.io but couldn't find a place to contact someone for the suggestion.

* Added additional details regarding the formatting of the example.

Signed-off-by: Chris Wessells <cwessells@silvervue.com>

README.md

@@ -173,11 +173,12 @@ describe sshd_config do
 end
 ```
 
-* Test your `kitchen.yml` file to verify that only Vagrant is configured as the driver.
+* Test your `kitchen.yml` file to verify that only Vagrant is configured as the driver.  The %w() formatting will
+pass rubocop lintng and allow you to access nested mappings.
 
 ```ruby
 describe yaml('.kitchen.yml') do
-  its('driver.name') { should eq('vagrant') }
+  its(%w(driver name)) { should eq('vagrant') }
 end
 ```