This required changing the `voted_before_sign_in` slightly in order to
change what the method returns if the user signed in and voted at the
exact same microsecond.
It doesn't affect production code because it would be impossible for the
user to do both things at the same time.
As a side effect, the method now returns what the method name suggests.
Before this change, the correct method name would have been
`voted_before_or_at_the_same_time_of_sign_in`.
As a less desirable side effect, in the tests now we need to make sure
at least one second passes between the moment a user votes and the
moment a user signs in again. One microsecond wouldn't work because
the method `travel_to` automatically sets microseconds to zero in order
to avoid rounding issues.
