'Post `words` and return current state for each user:
{username: json_state}'

def _post_words(self, words):

    users_state = {}
    for user in self.users:
        response = self.clients[user.username].post(self.get_url('submit'), {'student_words[]': words}, HTTP_X_REQUESTED_WITH='XMLHttpRequest')
        users_state[user.username] = json.loads(response.content)
    return users_state
