feat: Implement create folder API endpoint

packages/backend/src/serializers/folder.js

@@ -0,0 +1,10 @@
+const folderSerilializer = (folder) => {
+  return {
+    id: folder.id,
+    name: folder.name,
+    createdAt: folder.createdAt.getTime(),
+    updatedAt: folder.updatedAt.getTime(),
+  };
+};
+
+export default folderSerilializer;