Update CHANGELOG.markdown

Author: mbleigh

CHANGELOG.markdown

@@ -10,6 +10,7 @@ Next Release
 * [#203](https://github.com/intridea/grape/pull/203): Added a check to `Entity#serializable_hash` that verifies an entity exists on an object - [@adamgotterer](https://github.com/adamgotterer).
 * [#204](https://github.com/intridea/grape/pull/204): Added ability to declare shared parameters at namespace level - [@tim-vandecasteele](https://github.com/tim-vandecasteele).
 * [#208](https://github.com/intridea/grape/pull/208): `Entity#serializable_hash` must also check if attribute is generated by a user supplied block - [@ppadron](https://github.com/ppadron).
+* [#234](https://github.com/intridea/grape/pull/234): Adds a DSL for creating entities via mixin - [@mbleigh](https://github.com/mbleigh).
 
 0.2.1 (7/11/2012)
 =================