docs(changelog): Add historical changelog entries.

docs/changelog.md

@@ -2,11 +2,10 @@
 
 This changelog is used to track all major changes to django_apscheduler.
 
-## v0.4.0 (UNRELEASED)
+## v0.4.0 (2020-07-27)
 
 **Enhancements**
 
-- Start maintaining changelog.
 - Drop support for Python 2.7, convert codebase to Python 3.6+.
 - CI: drop coverage for Python 2.7 and Django <= 2.1, which are no longer maintained upstream.
 - CI: add coverage for Python 3.7 and 3.8, as well as Django long term support (LTS) and the latest released versions.
@@ -15,7 +14,7 @@ This changelog is used to track all major changes to django_apscheduler.
 - Clean up unused dependencies / update dependencies to latest available versions.
 - Switch to Black code formatting.
 - Align package layout with official [Django recommendations](https://docs.djangoproject.com/en/dev/intro/reusable-apps/#packaging-your-app)
-- Move UI-related DjangoJobExecution.html_status out of model definition and in to the associated model admin definition.
+- Move UI-related `DjangoJobExecution.html_status` out of model definition and in to the associated model admin definition.
 - Add `help_text` to model fields to document their use.
 - Remove unused code fragments.
 - Add Python type annotations.
@@ -54,3 +53,75 @@ This changelog is used to track all major changes to django_apscheduler.
   store. This aligns with the behavior expected by the APScheduler interface. Use the `replace_existing` parameter to
   update existing jobs instead.   
 
+
+# v0.3.1 (2020-07-12)
+
+- Various bug fixes (see commit history for changes).
+
+
+## v0.3.0 (2019-04-03)
+
+- Added timezone support when rendering datetimes; dropped support for django1.8 (Fixes [#43](https://github.com/jarekwg/django-apscheduler/issues/43) - thanks @jcass77).
+- Added model manager for deleting old job executions (Fixes [#58](https://github.com/jarekwg/django-apscheduler/issues/58) - thanks @jcass77).
+
+
+## v0.2.13 (2018-09-01)
+
+- Fixed exception when removing failed jobs (Fixes [#33](https://github.com/jarekwg/django-apscheduler/issues/33)).
+- Accounted for `dt` coming in as `None` into `serialize_dt` (Fixes [#35](https://github.com/jarekwg/django-apscheduler/issues/35)).
+
+
+## v0.2.12 (2018-07-10)
+
+- Fix of [#26](https://github.com/jarekwg/django-apscheduler/issues/26).
+
+
+## v0.2.10 (2018-06-05)
+
+- This release covers this PR [#23](https://github.com/jarekwg/django-apscheduler/issues/23), thanks to @nialllo
+
+
+## v0.2.9 (2018-05-08)
+
+- Now `add_job` with duplicated job `id` will refresh job in database instead of raising an exception.
+
+
+## v0.2.8 (2018-04-28)
+
+- Fixed bug [#20](https://github.com/jarekwg/django-apscheduler/issues/20).
+- Changed logger from `default` to `django_apscheduler`.
+- Added `on_error_value` into `ignore_database_error` (to return empty array instead of `None` in some methods).
+- Added django==1.8 test env in tox.ini
+
+
+## v0.2.7 (2018-04-14)
+
+- Fixed issue (Fixes [#18](https://github.com/jarekwg/django-apscheduler/issues/18)).
+- Added check whether `connections.connection` is `None`.
+
+
+## v0.2.6 (2018-04-12)
+
+- This release closes bugs described in (Fixes [#15](https://github.com/jarekwg/django-apscheduler/issues/15)).
+- After updating, please run `./manage.py migrate django_apscheduler` to apply the latest database changes.
+
+
+## v0.2.5 (2018-02-01)
+
+- Fix [#13](https://github.com/jarekwg/django-apscheduler/issues/13).
+- Added exception handling when system tables doesn't exists
+
+
+## v0.2.3 (2017-12-10)
+
+- Underscore changed to hyphen in pypi package name.  
+
+
+## v0.2.2 (2017-12-10)
+
+- Django 2.x support.
+
+
+## Pre-releases
+
+- The project did not tag a number of pre-release versions.