Refactor Append-only Example from UUID to use CID

@nelsonic based on the following comment you made in here...

The work to make Phoenix append-only is "on-going". Once CID is complete we will need to integrate it into our Example: https://github.com/dwyl/phoenix-ecto-append-only-log-example and then add it to Alog (which will need to be re-worked to make the log "generic" ... tbd.)

Would I be correct in assuming that now that CID has been published, updating this example is the next priority (one of the next priorities) on the list?