Update CHANGELOG.md

Author: andreibondarev

CHANGELOG.md

@@ -1,4 +1,13 @@
-## [Unreleased]
+# CHANGELOG
+
+## Key
+- [BREAKING]: A breaking change. After an upgrade, your app may need modifications to keep working correctly.
+- [FEATURE]: A non-breaking improvement to the app. Either introduces new functionality, or improves on an existing feature.
+- [BUGFIX]: Fixes a bug with a non-breaking change.
+- [COMPAT]: Compatibility improvements - changes to make Administrate more compatible with different dependency versions.
+- [OPTIM]: Optimization or performance increase.
+- [DOCS]: Documentation changes. No changes to the library's behavior.
+- [SECURITY]: A change which fixes a security vulnerability.
 
 ## [0.1.12] - 2024-09-20
 - Adding `rails g langchainrb_rails:assistant --llm=...` generator