Class QuestionId

ch_04/ch_04-s4.1.2/src/main.rs:52–52

#[derive(Serialize, Deserialize, Debug, Clone, PartialEq, Eq, Hash)]
struct QuestionId(String);

impl Question {
    fn new(id: QuestionId, title: String, content: String, tags: Option<Vec<String>>) -> Self {