add authentication check to prevent unauthenticated posts to /login containing a user
add authentication check to prevent unauthenticated posts to /login containing a user

previously you could use postman to send a POST request to /login and
could be authenticated since the only check in the route was for
presence of a user object.  Now, passport's isAuthenticated session
property is used to only allow truly authenticated users to login and go
to customers/home

cap9090/cs546FinalProject,cap9090/cs546FinalProject