Update the changelog

CHANGELOG.md

@@ -4,6 +4,29 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/)
 and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.html).
 
+## [0.4.0] - 2023-02-25
+
+### Removed
+
+- Removed `EventFragment` class. The `Event` class is no longer a Value Object. In other words, it is no longer
+immutable and it may be invalid by not having attributes `id` or `sig`. The `EventFragment` abstraction, along with the
+principles of immutability and was a major source of internal complexity as I needed to scale the codebase.
+
+### Added
+
+- Client compliance with [NIP-04](https://github.com/nostr-protocol/nips/blob/master/04.md) (encrypted direct messages)
+- Extracted the cryptographic concerns into a `Crypto` class.
+- Added the setters `Event#id=` and `Event#sig=`
+- Added a method on the event class to sign events (`Event#sign`)
+- Added a missing test for `EventKind::CONTACT_LIST`
+- Added two convenience methods to append event and pubkey references to an event's tags `add_event_reference` and
+`add_pubkey_reference`
+
+### Fixed
+
+- Fixed the generation of public keys
+- Fixed the RBS signature of `User#create_event`
+
 ## [0.3.0] - 2023-02-15
 
 ### Added