'Update token given data from OAuth response
Expect the following response into the closure::
u\'token_type\': u\'bearer\',
u\'scopes\': u\'webhook repository team account\',
u\'refresh_token\': u\'...\',
u\'access_token\': u\'...\',
u\'expires_in\': 3600,
u\'expires_at\': 1449218652.558185'

def token_updater(self, token):

    def _updater(data):
        token.token = data['access_token']
        token.expires_at = datetime.fromtimestamp(data['expires_at'])
        token.save()
        log.info('Updated    token    %s:', token)
    return _updater
