Can request & respond to rematch

rust/sea_battle_backend/src/data/current_game_status.rs

@@ -300,6 +300,12 @@ impl CurrentGameStatus {
             BotType::Smart => self.find_smart_bot_fire_location(),
         }
     }
+
+    /// Check out whether game is over or not
+    pub fn is_game_over(&self) -> bool {
+        self.opponent_map.sunk_boats.len() == self.rules.boats_list().len()
+            || self.your_map.sunk_boats.len() == self.rules.boats_list().len()
+    }
 }
 
 #[cfg(test)]