Update documentation

vagrant · vagrant · commit 323b368de354 · 2018-06-03T14:19:23.000Z
diff --git a/README.md b/README.md
@@ -131,6 +131,9 @@ If the resource has been updated before your update attempt, then the above will
 update **no** records and it means that the model has been updated before
 current attempt or it has been deleted.
 
+### Why don't we use `updated_at` for tracking changes?
+Because they may remain the same during two concurrent updates.
+
 ## Running tests
 Clone the repo, perform a composer install and run:
 
