Add 'nested validation' to changelog.

Author: Tim Vandecasteele

CHANGELOG.markdown

@@ -1,6 +1,7 @@
 Next Release
 ============
 
+* [#236](https://github.com/intridea/grape/pull/236): Allow validation of nested parameters. - [@tim-vandecasteele](https://github.com/tim-vandecasteele).
 * [#201](https://github.com/intridea/grape/pull/201): Added custom exceptions to Grape. Updated validations to use ValidationError that can be rescued. - [@adamgotterer](https://github.com/adamgotterer).
 * [#211](https://github.com/intridea/grape/pull/211): Updates to validation and coercion: Fix #211 and force order of operations for presence and coercion - [@adamgotterer](https://github.com/adamgotterer).
 * [#210](https://github.com/intridea/grape/pull/210): Fix: `Endpoint#body_params` causing undefined method 'size' - [@adamgotterer](https://github.com/adamgotterer).