Warning about using the default password.

Change the default password, please :)
> Does this slow things down much? It feels a bit overkill to check it on every pageload, especially even after they've changed the password.

@mjangda I had the same thought at the last minute which is why I ended up submitting a PR for this. I would rather set the password to a random string, but I'm not sure how we would send it to the user :)

I'll think about this some more.