Adds now unique ID to the challenge files unless it already exists.
Adds now unique ID to the challenge files unless it already exists.

kevinnorris/arcade-mode,kevinnorris/arcade-mode,kevinnorris/arcade-mode,freeCodeCamp/arcade-mode,freeCodeCamp/arcade-mode,freeCodeCamp/arcade-mode,freeCodeCamp/arcade-mode,kevinnorris/arcade-mode