doesn't fetch a new user after logout (exercise 8)

[mickeypuri]

if you create two users, and log out, then on logging back in, you find that we don't actually fetch a new user, as the logout does not remove the user from the store, and the new login doesn't fetch a user as there already is one in the store.

dont think this prevents the learning of hooks, but it would be good to tidy it up. If you want me to put it right, let me know, its a very straightforward fix.