there's no way to do it.

1. the only unique identifier we can use other than id is app name.
2. manifest is not trustworthy because the real app name in DB is defined when app is created through api, not the one specified in manifest.
3. the existence of app_id cache is also not trustworthy because it's more likely people create app through the web interface, they will have to then find the app id by typing in the app name in zat when doing `update`