Add developer documentation on the release process

development.md

@@ -0,0 +1,37 @@
+# Information for developers
+
+## Release management
+To create a new release for smesh, perform the following steps:
+1) Make sure that all PRs and changes that you want to go into the release are merged to
+   `main` and that the latest commit on `main` has passed all CI tests.
+2) Determine the currently released version of Smesh.jl, e.g., on the
+   [release page](https://github.com/trixi-framework/smesh/releases). For this manual,
+   we will assume that the latest release was `v0.2.3`.
+3) Decide on the next version number. We follow [semantic versioning](https://semver.org/),
+   thus each version is of the form `vX.Y.Z` where `X` is the major version, `Y` the minor
+   version, and `Z` the patch version. In this manual, we assume that the major version is
+   always `0`, thus the decision process on the new version is as follows:
+   * If the new release contains *breaking changes* (i.e., user code might not work as
+     before without modifications), increase the *minor* version by one and set the
+     *patch* version to zero. In our example, the new version should thus be `v0.3.0`.
+   * If the new release only contains minor modifications and/or bug fixes, the *minor*
+     version is kept as-is and the *patch* version is increased by one. In our example, the
+     new version should thus be `v0.2.4`.
+4) Edit the string in the
+   [`VERSION`](https://github.com/trixi-framework/Smesh.jl/blob/main/VERSION)
+   and set it to the new version. Push/merge this change to `main`.
+5) Go to GitHub and create a new release, either by going to the
+   [release page](https://github.com/trixi-framework/smesh/releases) and clicking on "Draft
+   a new release" or by directly following
+   [this link](https://github.com/trixi-framework/smesh/releases/new).
+   * Click on "Choose a tag", enter the new version (e.g., `v0.2.4`, *including* the `v`
+     prefix), and select "Create a new tag".
+   * Click on "Generate release notes".
+   * Click on "Publish release".
+7) The new release is immediately usable and visible on the release page \o/
+8) To make sure people do not mistake the latest state of `main` as the latest release, we
+   set the version in the `Project.toml` to a *development* version. The development version
+   should be the latest released version, with the patch version incremented by one, and the
+   `-dev` suffix added. For example, if you just released `v0.3.0`, the new development
+   version should be `v0.3.1-dev`. If you just released `v0.2.4`, the new development
+   version should be `v0.2.5-dev`.