indicate in game state whose turn it is

game/game.go

@@ -237,6 +237,7 @@ func (g *Match) DTO(id player.ID) serve.Game {
 			g.players[1].DTO(),
 		},
 		Round:    g.round,
+		Dealer:   g.CurrentPlayer() == &g.players[0],
 		Damage:   g.damage,
 		Shell:    g.Peek(id),
 		Previous: g.prev,

game/game_test.go

@@ -445,6 +445,7 @@ func TestGameDTO(t *testing.T) {
 				g.players[1].DTO(),
 			},
 			Round:    g.round,
+			Dealer:   false,
 			Damage:   g.damage,
 			Shell:    nil,
 			Previous: nil,
@@ -469,6 +470,7 @@ func TestGameDTO(t *testing.T) {
 				g.players[1].DTO(),
 			},
 			Round:    g.round,
+			Dealer:   true,
 			Damage:   g.damage,
 			Shell:    nil,
 			Previous: &g.shellArray[0],