public String getUsers(String app_key, String userKey) {
        try {
            app_key = URLEncoder.encode(app_key, "UTF-8");
            userKey = URLEncoder.encode(userKey, "UTF-8");
        } catch (UnsupportedEncodingException e) {
            BmLog.error(e);
        }
        return String.format("%s/api/latest/users/?app_key=%s&api-key=%s", SERVER_URL, app_key, userKey);
    }