added command sample

command/src/main/java/com/iluwatar/Visibility.java

@@ -0,0 +1,26 @@
+package com.iluwatar;
+
+public enum Visibility {
+
+	VISIBLE,
+	INVISIBLE;
+
+	@Override
+	public String toString() {
+		
+		String s = "";
+		
+		switch (this) {
+		case INVISIBLE:
+			s = "invisible";
+			break;
+		case VISIBLE:
+			s = "visible";
+			break;
+		default:
+			break;
+		
+		}
+		return s;
+	}
+}