docs: update CHANGELOG

CHANGELOG.md

@@ -7,6 +7,11 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Added
+
+- `owners` optional field in `Host` model as many-to-many reference to `User` (steering#166)
+- `language` and `topic` optional fields in `Timeslot` model (steering#169)
+
 ### Changed
 
 - `note_id` and `show_id` are read-only fields of the `TimeslotSerializer` (steering#171)