Added DAO implementation, modified readme, and added UML diagram

dao/src/test/java/com/iluwatar/AppTest.java

@@ -0,0 +1,12 @@
+package com.iluwatar;
+
+import org.junit.Test;
+
+public class AppTest {
+
+	@Test
+	public void test() {
+		String[] args = {};
+		App.main(args);
+	}
+}