Add RubyComments linter

Add a simple linter which enforces the use of HAML comments over ad hoc
comments in Ruby code.

Change-Id: I0c8177a32fc966c2247d92ba0d6abbac3874ba33
Reviewed-on: http://gerrit.causes.com/42346
Tested-by: jenkins <jenkins@causes.com>
Reviewed-by: Shane da Silva <shane.dasilva@brigade.com>