Move to entity structs

src/entity/hand.go

@@ -0,0 +1,17 @@
+package entity
+
+type Hand struct {
+	Public  []Card
+	Private []Card
+}
+
+func (hand *Hand) Push(card Card) {
+	if hand.Public == nil {
+		hand.Public = make([]Card, 0, 1)
+	}
+	hand.Public = append(hand.Public, card)
+}
+
+func (hand Hand) Len() int {
+	return len(hand.Public) + len(hand.Private)
+}