docs: document how to create a release

docs/RELEASE.md

@@ -0,0 +1,44 @@
+# Release
+
+## How to Create a Release
+
+1. Create a git tag for the new release
+
+   ```sh
+   git tag v<MY-VERSION>
+   ```
+
+   **ADVISE**: Do not push the tag. Instead let it be created by GitHub when
+   removing the draft status. This allows to eventually recreate + delete the
+   draft release without having the tags already on the on the git remote.
+
+2. Import our GPG signing private key:
+   - retrieve the GPG private key password and store it in an environment
+     variable:
+
+       ```sh
+       export GPG_PASSWORD="$(vault read -field=master-priv-key-password secret/gpg-key-platform)"
+       ```
+
+   - import the signing key:
+
+       ```sh
+       vault read -field=subkey-signing-priv-key  secret/gpg-key-platform | \
+           gpg --batch --pinentry-mode loopback --passphrase "$GPG_PASSWORD" --import
+       ```
+
+3. Set the `GITHUB_TOKEN` environment variable:
+
+   ```sh
+   export GITHUB_TOKEN=<MY-TOKEN>
+   ```
+
+4. Run goreleaser
+
+    ```sh
+    goreleaser release
+    ```
+
+5. Review the created draft release on
+   [GitHub](https://github.com/simplesurance/registrator/releases) and publish
+   it.