Update changelog

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 5158e284feb1ce0229719e2c787b804a1fd28cec..f53d1789d5f37c1d91f36d69d47012590e649044 100644 (file)
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -8,6 +8,8 @@ The format is based on [Keep a Changelog][] and this project adheres to
 [Semantic Versioning]: http://semver.org/
 
 ## Unreleased
+### Added
+- 2d grid data structure for indexing nodes by `x` and `y` axes.
 
 ## 0.4.0 - 2019-01-16
 ### Added