feat: Ensure consistent ordering of games, users, and user opinions, and add DerefMut for User.

backend/src/store.rs

@@ -17,6 +17,12 @@ impl std::ops::Deref for User {
     }
 }
 
+impl std::ops::DerefMut for User {
+    fn deref_mut(&mut self) -> &mut Self::Target {
+        &mut self.person
+    }
+}
+
 #[derive(Serialize, Deserialize)]
 pub struct PersistentState {
     pub games: Vec<Game>,
@@ -26,10 +32,17 @@ pub struct PersistentState {
 pub const STATE_FILE: &str = "state.json";
 
 pub fn save_state(games: &[Game], users: &[User]) {
-    let state = PersistentState {
-        games: games.to_vec(),
-        users: users.to_vec(),
-    };
+    let mut games = games.to_vec();
+    games.sort_unstable_by(|g1, g2| g1.title.cmp(&g2.title));
+
+    let mut users = users.to_vec();
+    users.sort_unstable_by(|u1, u2| u1.name.cmp(&u2.name));
+
+    users.iter_mut().for_each(|u| {
+        u.opinion.sort_unstable_by(|o1, o2| o1.title.cmp(&o2.title));
+    });
+
+    let state = PersistentState { games, users };
     if let Ok(file) = File::create(STATE_FILE) {
         let _ = serde_json::to_writer_pretty(file, &state);
     }