Improve caching, move mutex to the cache implementation

application/application.go

@@ -20,7 +20,7 @@ func NewApplication(ctx context.Context, cfg Config, logger *zap.Logger) (*Appli
 		return nil, fmt.Errorf("new db: %w", err)
 	}
 
-	cache := make(inmemorycache.Cache)
+	cache := inmemorycache.NewCache()
 
 	repo, err := repository.NewConnLogs(ctx, db, cache, logger, cfg.UpdateInterval)
 	if err != nil {