Proper initial db selection (e.g. when 'admin' doesn't exist)

[vasiltabakov]

There's no default 'admin' db on my system, for whatever reason. So the script fails. It's easy enough to replace the default db to something I know exists on the system, but why not let the script select any (random?) db. What if there are no db's at all?

[lovetheidea]

Looking for any who can improve this for us. Making the process of setup + installing light speed quick. If you don't have MongoDB drivers installed / no DB / default settings like Wordpress setup.