Game object rotate with the camera on y axis

Hello, I'm pretty new to game developing and I have a vr game idea that I'm trying to create. Right now I'm just trying to figure out how to attach a game object to the vr camera so that it moves/rotates with the camera but only on the Y axis.

So basically I want to make a game object like a cube rotate on the Y axis with the vr camera but stay stationary. I really don't know much how to script. I tried parenting the cube and then added a character joint which kind of worked but was buggy. Any help is much appreciated.