Add unit test.

service-layer/src/test/java/com/iluwatar/AppTest.java

@@ -1,4 +1,12 @@
 package com.iluwatar;
 
+import org.junit.Test;
+
 public class AppTest {
+	
+	@Test
+	public void test() {
+		String[] args = {};
+		App.main(args);
+	}
 }