Any reason the plugin itself doesn't work for you? It does require you to actually click the button to create the post, although I assume it can be automated for Ghost (we just tended to make it a little more generic so it works with WordPress, etc.)
Override nodebb login
I have website where users data with username and password is stored, is there any plugin to use the data in my database to directly register and login in nodebb?
You're looking for an SSO plugin or the Session Sharing plugin.