Updated gem file for git duet.

Signed-off-by: Scott Skender <sjskender@gmail.com>
Refactored code to associate items with an id

This was catalyzed by beginning to write the show item test
We made enough changes in the refactoring that felt it was worth committing to continue onward with the show item spec.

Signed-off-by: Scott Skender <sjskender@gmail.com>