Auth token not stored on initial sign-in

[cecilia-donnelly]

On the add-oauth-signin branch, users should be able to click "Sign in with Google" and immediately see results from their searches. Right now, though, a user has to click the button again after signing in before the id_token is saved correctly and API requests will succeed. I assume this will get fixed as I complete the authentication functionality, but I wanted to record it so I don't forget.

(We probably want to change the flow here so that a user would see a login page first, and then after logging in would see the search page -- but for now, this should work as expected.)