Sample External KeyManager for Authen Pluggable Captcha

This code requires Rose::DB::Object to run, but it could be implemented in a non-rose manner

postgres=# create user keymanager with password 'keymanager';
CREATE ROLE
postgres=# create database keymanager with owner = keymanager ENCODING = 'UTF8' TABLESPACE = pg_default;
CREATE DATABASE


create table captcha_key ( 
	id bigserial primary key , 
	hex_id char(32) not null,
	is_valid boolean default true,
	timestamp_created timestamp not null,
	ip_created varchar(15) null,
	timestamp_used timestamp null,
	ip_used varchar(15) null
);

connect args are in 

	Authen::PluggableCaptcha::KeyManagerDB::RoseDB

overrides are via the following envelope args

$ENV{'Authen::PluggableCaptcha::KeyManagerDB::RoseDB::driver'}= 'Pg';
$ENV{'Authen::PluggableCaptcha::KeyManagerDB::RoseDB::database'}= 'keymanager';
$ENV{'Authen::PluggableCaptcha::KeyManagerDB::RoseDB::host'}= 'localhost';
$ENV{'Authen::PluggableCaptcha::KeyManagerDB::RoseDB::username'}= 'keymanager';
$ENV{'Authen::PluggableCaptcha::KeyManagerDB::RoseDB::password'}= 'keymanager';




