indicate in game state whose turn it is

serve/dto.go

@@ -9,6 +9,8 @@ type Game struct {
 	Players [2]Player `json:"players"`
 	// Round is the current round.
 	Round int8 `json:"round"`
+	// Dealer indicates whether the current player is the dealer.
+	Dealer bool `json:"dealer"`
 	// Damage is the damage a live shell will deal this turn.
 	Damage int8 `json:"damage"`
 	// Shell gives whether the current shell is live if it is revealed.