def add_dashes(uuid)
      return uuid if uuid =~ /\-/
      [uuid[0..7], uuid[8..11], uuid[12..15], uuid[16..19], uuid[20..-1]].join("-")
    end
def add_dashes(uuid)
      return uuid if uuid =~ /\-/
      [uuid[0..7], uuid[8..11], uuid[12..15], uuid[16..19], uuid[20..-1]].join("-")
    end
A UUID consists of 5 groups of characters.
   8 chars - 4 chars - 4 chars - 4 chars - 12 characters

 This function re-introduces the dashes since we removed them during
 serialization, so:

   add_dashes("2b4a233152694c6e9d1e098804ab812b")
     => "2b4a2331-5269-4c6e-9d1e-098804ab812b"