Those generators were for old-style “plugins” which have been deprecated by Rails. Now we need “gems” which is what we’ve been doing migrating everything from ./vendor/plugins/ to their own repos (e.g. dradis-csv, dradis-nessus, etc.). We call these new style plugins “add-ons”, and you can see a full list of add-ons here:
Your best bet today is to copy the code from some of these add-ons and adjust it to your needs.
Fear not though, we’re working on step-by-step guides to create different add-ons, we’ll start with Export and Upload add-ons. Will keep you posted.