Isn't having a free will a contradiction when God knows our future?

according to Christian doctrine, God knows all real things in the past, the present and the future. By the knowledge of vision, God also foresees the future free acts of rational creatures with infallible certainty. God, by His eternal resolve of Will, has predetermined certain men to eternal blessedness. God, by an eternal resolve of His Will, predestines certain men, on account of their foreseen sins, to eternal rejection. How can we have free will when God knows our future? This to me sounds like a contradiction.