Update the readme and scripts to reflect zuul instead of tidepool-groupedit

I preserved the old addToCareteam.sh script as addToCareteamGroupedit.sh so that it is simple to have users use the old script if they have problems with the new one for some reason.

@kentquirk Just went to update things and realized that the script that we are using is a part of this repo.  Also realized I hadn't updated the readme, so I've done both of those in this PR.