Class Question

ch_04/final/src/main.rs:14–19

#[derive(Deserialize, Serialize, Debug, Clone)]
struct Question {
    id: QuestionId,
    title: String,
    content: String,
    tags: Option<Vec<String>>,
}
#[derive(Deserialize, Serialize, Debug, Clone, PartialEq, Eq, Hash)]
struct QuestionId(String);