player command

app/src/main/java/chess/io/commands/GrandCastlingCommand.java

@@ -1,15 +1,21 @@
 package chess.io.commands;
 
-import chess.io.Command;
 import chess.io.CommandResult;
 import chess.io.OutputSystem;
+import chess.io.PlayerCommand;
 import chess.model.Game;
 
-public class GrandCastlingCommand extends Command{
+public class GrandCastlingCommand extends PlayerCommand {
 
 	@Override
 	public CommandResult execute(Game game, OutputSystem outputSystem) {
 		return CommandResult.NotAllowed;
 	}
-	
+
+	@Override
+	public void undo(Game game, OutputSystem outputSystem) {
+		// TODO Auto-generated method stub
+		throw new UnsupportedOperationException("Unimplemented method 'undo'");
+	}
+
 }