This is to add a new section for Gerritt testing.

This is so a new person can read the docs and understand what the steps
are to start commiting code to http://review.openstack.org.
Merge pull request #299 from opscode/testing_Gerritt

This is to add a new section for Gerritt testing.
hook in new gerrit topic
add Gerritt to official names list; hook in
remove warning
add note w/link to ohai plugin examples
add chef-metal
stub chef_metal topic; hook in resources
add more info
add example
remove placeholders for examples
remove placeholders for examples
edits
set include
add knife[:dockerfiles]
fix setting name
fix link path
update syntax
add ntp for getting started
add page for chef-dk to improve search results