Document how we do releases (#315)

- Introducing a Changelog file
- Describe how we release

CHANGELOG.md

@@ -0,0 +1,26 @@
+# 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).
+
+For each Pull Request, the affected code parts should be briefly described and added here in the "Upcoming" section.
+Once a release is done, the "Upcoming" section becomes the release changelog, and a new empty "Upcoming" should be
+created.
+ 
+## Upcoming
+
+### Added
+
+### Changed
+
+### Fixed
+
+### Removed
+
+### Deprecated
+
+
+
+## 0.1 (2020-11-13)
+- This is the baseline release.

README.md

@@ -102,6 +102,8 @@ Further detailed instructions, including setup in Azure, are here:
 ## More information
 
 1. [Project InnerEye](https://www.microsoft.com/en-us/research/project/medical-image-analysis/)
+1. [Releases](docs/releases.md)
+1. [Changelog](CHANGELOG.md)
 1. [Testing](docs/testing.md)
 1. [How to do pull requests](docs/pull_requests.md)
 1. [Contributing](docs/contributing.md)

docs/releases.md

@@ -0,0 +1,12 @@
+# Releases
+
+The InnerEye toolbox is in an early stage, where many of its inner workings are changing rapidly. However, the
+purely config-driven approach to model building should remain stable. That is, you can expect backwards
+compatibility if you are building models by creating configuration files and changing the fields of the classes 
+that define, say, a segmentation model. The same goes for all Azure-related configuration options.
+If your code relies on specific functions inside the InnerEye code base, you should expect that this can change.
+
+The current InnerEye codebase is not published as a Python package, and hence does not have implicit version numbers.
+We are applying tagging instead, with increases corresponding to what otherwise would be major/minor versions. 
+
+Please refer to the [Changelog](../CHANGELOG.md) for an overview of recent changes.

pull_request_template.md

@@ -2,9 +2,11 @@ Write a detailed description of your PR here.
 
 Please follow the guidelines for PRs contained [here](docs/pull_requests.md). Checklist:
 
-- [ ] Your PR is small, and implements one change.
-- [ ] You have added unit tests for all functions that you modified.
-- [ ] You have run PyCharm's code cleanup tools on your Python files.
+- [ ] Ensure that your PR is small, and implements one change.
+- [ ] Add unit tests for all functions that you introduced or modified.
+- [ ] Run PyCharm's code cleanup tools on your Python files.
 - [ ] Link the correct GitHub issue for tracking.
+- [ ] Update the [Changelog](CHANGELOG.md) file: Describe your change in terms of 
+Added/Changed/Removed/... in the "Upcoming" section.
 - [ ] When merging your PR, replace the default merge message with a description of your PR,
 and if needed a motivation why that change was required.