'Add a user\'s server to the proxy table.'

@gen.coroutine
def add_user(self, user, server_name='', client=None):

    spawner = user.spawners[server_name]
    self.log.info('Adding    user    %s    to    proxy    %s    =>    %s', user.name, spawner.proxy_spec, spawner.server.host)
    if spawner._spawn_pending:
        raise RuntimeError("User    %s's    spawn    is    pending,    shouldn't    be    added    to    the    proxy    yet!", user.name)
    (yield self.add_route(spawner.proxy_spec, spawner.server.host, {'user': user.name, 'server_name': server_name}))
