change project structure

app/src/main/java/chess/controller/commands/CastlingCommand.java

@@ -0,0 +1,24 @@
+package chess.controller.commands;
+
+import chess.controller.OutputSystem;
+import chess.controller.PlayerCommand;
+import chess.model.Game;
+
+public class CastlingCommand extends PlayerCommand {
+
+	@Override
+	public CommandResult execute(Game game, OutputSystem outputSystem) {
+		// we must promote the pending pawn before
+		if (game.pawnShouldBePromoted())
+			return CommandResult.NotAllowed;
+
+		return CommandResult.NotAllowed;
+	}
+
+	@Override
+	public void undo(Game game, OutputSystem outputSystem) {
+		// TODO Auto-generated method stub
+		throw new UnsupportedOperationException("Unimplemented method 'undo'");
+	}
+
+}