added changelog

CHANGELOG.md

@@ -0,0 +1,15 @@
+# Changelog
+
+All notable changes to this project will be documented in this file.
+
+The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
+and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
+
+# [0.0.0]
+
+## Features
+
+- Initial implementation of genogrove (Interval B+ Tree Library for C++)
+    - Supports insertion, search, and overlap queries
+    - Supports heterogeneous data types (returns any data as std::any)
+    - Native implementation of the Interval B+ Tree data structure (in C++20)