I have no idea how to get rid of them, but at first I was excited to see them! I've just started a vegetable garden and when I saw the mushrooms, which NEVER grew previously, I thought I was getting free mushrooms to eat. I looked it up on google to see what kind they were and if they could be eaten, but couldn't find a picture of the ones growing. I decided not to take any chances and just keep pulling them out.
Good luck with getting rid of them. All of a sudden they're popping up like crazy.