Correctly initialize new PhortuneAccount automatically

Summary: There is currently a validation error triggered if you initialize a new account without a member set. I think this is the correct fix, but let me know.

Test Plan: truncate phortune_account database, navigate to phortune, see account automatically created to "Default Account".

Reviewers: epriestley

Reviewed By: epriestley

Subscribers: Korvin

Differential Revision: https://secure.phabricator.com/D17657