cheat sheets.

Reserved Keywords in Ruby
-------------------------

  alias
  and
  BEGIN
  begin
  break
  case
  class
  def
  defined
  do
  else
  elsif
  END
  end
  ensure
  false
  for
  if
  in
  module
  next
  nil
  not
  or
  redo
  rescue
  retry
  return
  self
  super
  then
  true
  undef
  unless
  until
  when
  while
  yield