Update CHANGELOG

Author: febeling

CHANGELOG.md

@@ -2,12 +2,12 @@
 All notable changes to this project will be documented in this file.
 This project adheres to [Semantic Versioning](http://semver.org/).
 
-## [Unreleased][unreleased]
-### Fixed
-- Fix a bug in `Libsvm::Node#==` when comparing with `nil`.
-
+## [1.4.0] - 2015-09-18
 ### Changed
 - Complete transition to `expect` specs.
+- Raise exception in `Libsvm::Model.load` if model can't be loaded (fixes #21).
+### Fixed
+- Fix a bug in `Libsvm::Node#==` when comparing with `nil`.
 
 ## [1.3.1] - 2015-03-21
 ### Fixed