Remove `UserModel.find_by_sub` and replace usage with `UserModel.find_by_email`. Also remove `check_user_exists`. This will affect CLI command arguments. Also remove the index on `UserModel.sub`.
Remove
UserModel.find_by_suband replace usage withUserModel.find_by_email. Also removecheck_user_exists.This will affect CLI command arguments.
Also remove the index on
UserModel.sub.