code: public void uploadUsers(String hashAlgorithm, byte[] hashKey, List<GitkitUser> users)
        throws GitkitServerException, GitkitClientException {
        uploadUsers(hashAlgorithm, hashKey, users, null, null, null);
    }
docs: Uploads multiple user accounts to Gitkit server.
  
  @param hashAlgorithm hash algorithm. Supported values are HMAC_SHA256, HMAC_SHA1, HMAC_MD5,
  PBKDF_SHA1, MD5 and SCRYPT.
  @param hashKey key of hash algorithm
  @param users list of user accounts to be uploaded
  @throws GitkitClientException for invalid request
  @throws GitkitServerException for server error