Initial work on a new reference section.
Added a link to the reference files from the main railsbridge index.
Added a few commands to the cheet sheet.
Added a few commands to the cheet sheet.
Corrected a comment.
Reorganized. Moving the references into the intermediate directory for now. Eventually we need a way to make them common across both the beginner and intermediate left navs. Removed the references index because it was duplicating it's own left nav and looked a mess.
Merge branch 'master' into the-quick-brown-reference-jumps-over-the-lazy-curriculum
Edits for 'creating a new controller' page

class => controller
method => action
directory names (/views, /controller) are plural
use 'about' instead of 'new' for second action to avoid confusion
  with standard actions