Revert "Delete ShoppingListApplication.java"

This reverts commit 640bb544e6.

hexagonal-architecture-example/src/main/java/ShoppingListApplication.java

@@ -0,0 +1,12 @@
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+@SpringBootApplication
+public class ShoppingListApplication {
+
+	public static void main(String[] args) {
+		SpringApplication.run(ShoppingListApplication.class, args);
+	}
+
+}