clean up effects

effect.go

@@ -25,15 +25,15 @@ func RemoveEffect(source uuid.UUID, c *Card) {
 
 func AddEffect(c *Card, e *Effect) {
 	if c.Type == EmptyValue {
-		log.Println("Can't add effect to empty card")
+		//can't apply effect to empty card
 		return
 	}
-	if c.Position < 0 {
+	if c.Position < 0 || c.Position > 3 {
 		log.Println("trying to apply effect to card not on the board")
 	}
 	for _, v := range c.Effects {
 		if v.Owner == e.Owner && v.ID == e.ID && v.Target == e.Target {
-			log.Println("can't stack effects")
+			//can't stack effects
 			return
 		}
 	}