Update README and CHANGELOG regarding #484 [ci skip]

CHANGELOG.md

@@ -9,6 +9,8 @@ PaperTrail::Rails::Engine.eager_load!
 
 If you depend on the `RSpec` or `Cucumber` helpers, you will need to [manually load them into your test helper](https://github.com/airblade/paper_trail#testing).
 
+  - [#484](https://github.com/airblade/paper_trail/pull/484) - Support for
+    [PostgreSQL's JSONB Type](http://www.postgresql.org/docs/9.4/static/datatype-json.html) for storing `object` and `object_changes`.
   - [#458](https://github.com/airblade/paper_trail/pull/458) - For `create` events, metadata pointing at attributes should attempt
     to grab the current value instead of looking at the value prior to the change (which would always be `nil`)
   - [#440](https://github.com/airblade/paper_trail/pull/440) - `versions` association should clear/reload after a transaction rollback.

README.md

@@ -954,7 +954,7 @@ A valid serializer is a `module` (or `class`) that defines a `load` and `dump` m
 ### PostgreSQL JSON column type support
 
 If you use PostgreSQL, and would like to store your `object` (and/or `object_changes`) data in a column of
-[type `JSON`](http://www.postgresql.org/docs/9.4/static/datatype-json.html),
+[type `JSON` or type `JSONB`](http://www.postgresql.org/docs/9.4/static/datatype-json.html),
 specify `json` instead of `text` for these columns in your migration:
 
 ```ruby