Update CHANGELOG.md to with changes from PR #1860

CHANGELOG.md

@@ -32,6 +32,7 @@ This project adheres to [Semantic Versioning](http://semver.org/).
 * `#default_url` now accepts the same args passed to `#url` (@shekibobo [#1347](https://github.com/carrierwaveuploader/carrierwave/pull/1347))
 * Accept an array of strings or regexps to white/blacklist content types (@mehlah [#1816](https://github.com/carrierwaveuploader/carrierwave/pull/1816))
 * `#content_type_whitelist` and `extension_whitelist` now takes either a string, a regexp, or an array of values (same thing for blacklists) (@mehlah [#1825](https://github.com/carrierwaveuploader/carrierwave/pull/1825))
+* Blank uploaders are now memoized on the model instance (@DarthSim [#1860](https://github.com/carrierwaveuploader/carrierwave/pull/1860))
 
 ### Removed
 * Remove `CarrierWave::MimeTypes` processor module (@mehlah [#1813](https://github.com/carrierwaveuploader/carrierwave/pull/1813))