CHANGELOG.md in image_optimizer-1.7.1 vs CHANGELOG.md in image_optimizer-1.7.2

@@ -1,2 +1,5 @@
+## [1.7.2](https://github.com/jtescher/image_optimizer/releases/tag/v1.7.2) 2018-01-10
+* Added quiet option support for pngquant optimizer - https://github.com/jtescher/image_optimizer/pull/19
+
 ## [1.7.1](https://github.com/jtescher/image_optimizer/releases/tag/v1.7.1) 2017-11-29
 * Fix PNGQuantOptimizer `Unrecognised option` error - https://github.com/jtescher/image_optimizer/issues/17