If god knows everything past, present, and future, then why did he put the tree of knowledge in eden?

If god is all knowing and omnipotent than he knew that adam and eve would eat from the tree of knowledge if he put it there, and from that he would have to banish them and sin would be born. So why did he put the tree there if he didn't want man to know sin and be forced to condemn people to hell from that point on.