♻️Refactor : serializer 오타 수정 #3

- field -> fields로 수정

budget_management/users/serializers.py

@@ -6,7 +6,7 @@
 class UserSerializer(serializers.ModelSerializer):
     class Meta:
         model = User
-        field = ("username", "created_at", "updated_at")
+        fields = ("username", "created_at", "updated_at")
 
 
 class UserSignupSerializer(serializers.ModelSerializer):