feat(app): add application entry point and execution plugin

second-part/hw-02/user-service/src/main/java/com/example/Main.java

@@ -0,0 +1,17 @@
+package com.example;
+
+public class Main {
+
+  public static void main(String[] args) {
+    UserDao userDao = new UserDao();
+
+    User user = new User();
+    user.setName("User");
+    user.setEmail("user@example.com");
+    user.setAge(99);
+
+    userDao.create(user);
+
+    System.out.println(user);
+  }
+}