feat: init book handler

src/model/http_body/book.rs

@@ -0,0 +1,7 @@
+use serde::Serialize;
+
+#[derive(Serialize)]
+pub struct BookItem {
+    pub id: i64,
+    pub name: String,
+}

src/model/http_body/mod.rs

@@ -0,0 +1 @@
+pub mod book;