What does 1 Kings 22:15 mean?

When he arrived, the king asked, 'Micaiah, should we go to war against Ramoth-Gilead, or not?' Micaiah answered, 'Sure, go ahead and win. The Lord will give it to you.' 1 Kings 22:15 - Modern Text Bible

(Micaiah answers sarcastically, echoing the other prophets, making it clear he's not being serious.)