use pack_db::PackDb:
use serde::{Deserialize, Serialize};

#[derive(Debug, PartialEq, Deserialize, Serialize)]
struct User {
    name: String,
    age: i32
}

let store = PackDb::<User>::new(Some("data".to_owned()));
store.set("user1", User {name: "useer1", age: 16});
let user = store.get("user1");