I have this rig that I made. I was thinking that I could use some kind of IK system to make it easier to animate. But I have a problem with it. Either I'm not creating a proper IK system, or there is another issue. The thing is, I need the end bone (highlighted) to be straight and pointing up at all time. But when I use IK, it always rotate, which is not good. What would be the best way to deal with it?