README.md in smartsend-ruby-0.4.1 vs README.md in smartsend-ruby-0.4.2

@@ -148,5 +148,10 @@
 )
 
 account.valid?
   => false
 ```
+
+## Changelog
+
+### [0.4.2] - 2018-05-03
+* Changed `sub_total` to `subtotal`