Comments for observer example.

observer/src/main/java/com/iluwatar/App.java

@@ -1,5 +1,12 @@
 package com.iluwatar;
 
+/**
+ * 
+ * Observer pattern defines one-to-many relationship
+ * between objects. The target object sends change
+ * notifications to its registered observers.
+ *
+ */
 public class App 
 {
     public static void main( String[] args )