public function setAccessTokenExpire($access_token_expire)
    {
        //Store expiry date as unix timestamp (now + expires in)
        $access_token_expire = time() + $access_token_expire;
        $this->access_token_expire = $access_token_expire;
        $config = SiteConfig::current_site_config();
        $config->HailAccessTokenExpire = $access_token_expire;
        $config->write();
    }