At the moment Google Home does not support multiple users, it just treats all users as one user, although this will change in the future.
It has been revealed that Google Home will support multiple users in the future and Home will be able to recognize different voices of different people.
According to the guys over at Ausdroid, multiple user support is on its way to Google Home, you can see what Google has to say below.
It is not officially launched yet, it is some announcement that we are having to let our users know about the next update that we will release would allow multiple users.
Rest assured that once it is release your Google Home will get the latest update and notification from the app will be given in order for you to know that the feature is officially out.
As yet there are no details on when Google will add the multiple user support feature to Google Home, as soon as we get some more information, we will let you guys know.