Check the user authentication.

def authenticate(self):
        """Check the user authentication."""
        endpoint = os.path.join(self.config.get('napps', 'api'), 'auth', '')
        username = self.config.get('auth', 'user')
        password = getpass("Enter the password for {}: ".format(username))
        response = requests.get(endpoint, auth=(username, password))
        if response.status_code != 201:
            LOG.error(response.content)
            LOG.error('ERROR: %s: %s', response.status_code, response.reason)
            sys.exit(1)
        else:
            data = response.json()
            KytosConfig().save_token(username, data.get('hash'))
            return data.get('hash')