Added items method on storage.

src/storage.rs

@@ -42,6 +42,10 @@ impl Storage {
         &mut self.items[id]
     }
 
+    pub fn items(&mut self) -> impl Iterator<Item = &Item> {
+        self.items.iter()
+    }
+
     pub fn items_mut(&mut self) -> impl Iterator<Item = &mut Item> {
         self.items.iter_mut()
     }