Fix: some methods changed

backend/src/article/article.js

@@ -62,4 +62,4 @@ const ArticleSchema = new mongoose.Schema({
 
 const Article = mongoose.model("Article", ArticleSchema);
 
-export default Article;
\ No newline at end of file
+export default Article;

backend/src/user/userService.js

@@ -39,4 +39,4 @@ const userService = {
   }
 };
 
-export default userService;
\ No newline at end of file
+export default userService;