code: function getUIDCallback (err, uid) {
  		if (err) {
  			return onDone('UID_ERROR');
  		}
  		var ip = (extra) ? extra.conn.host : "server";
  		// NOTE: by default a user is a normal user, user 'groups' can later be customized
  		var reg = {
  			uid: 		uid,
  			account:	args.account,
  			password:	l_encryptPass(args.password),
  			email:		args.email,
  			// verify:		{email_verify: false, phone_verify: false},
  			tokens: 	{reset: '', pass: {}},
  			enc_type:	l_enc_type,
  			control:	{groups: args.groups || [], permissions: []},
  			data: 		args.data || {},
  			login: 		{IP: ip, count: 1}
  		};
  
  		// special handling (by default 'admin' account is special and will be part of the 'admin' group by default
  		if (!args.authWP && reg.account === 'admin') {
  			reg.control.groups.push('admin');
  		}
  
  		LOG.warn('creating new account [' + args.account + ']...', l_name);
  		l_accounts.add(reg, function (err) {
  			if (err) {
  				return onDone('DB_ERROR', err);
  			}
  			// register success
  			LOG.warn('account register success', l_name);
  			onDone(null);
  		});
  	}
docs: generate unique user_id