Update README.md

Author: ji-hoooon

README.md

@@ -42,7 +42,11 @@ JUnit
 * ERD 
 
 ![ERD](https://user-images.githubusercontent.com/37648641/233539052-1d19db0c-6608-4578-8259-adcf72253a39.png)
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+* 패키지 다이어그램
+
+![패키지 다이어그램](https://user-images.githubusercontent.com/37648641/233544218-6a203b37-8ab8-4c2c-9436-0260839c5f5d.png)
+
 * 클래스 다이어그램
 
 ![mvc구조도.png](MVC구조도.png)