change project structure

app/src/main/java/chess/controller/Command.java

@@ -0,0 +1,21 @@
+package chess.controller;
+
+import chess.model.Game;
+
+public abstract class Command {
+
+	public enum CommandResult {
+		/** The command was successfull. Should update display and switch player turn. */
+		Moved,
+		/** The command was successfull. Should not update anything */
+		NotMoved,
+		/** The command was successfull. Should only update display */
+		ActionNeeded,
+		/** The command was not successfull */
+		NotAllowed;
+	}
+
+	public abstract CommandResult execute(Game game, OutputSystem outputSystem);
+
+	public void postExec(Game game, OutputSystem outputSystem) {}
+}