fixed warning in console

app/src/components/blog/Overview.hx

@@ -20,7 +20,7 @@ class Overview extends ReactComponent {
     private static function printList(){
         var result = [];
         for (item in items){
-            result.push(jsx('<li>$item</li>'));
+            result.push(jsx('<li key="$item">$item</li>'));
         }
         return result;
     }