docs: add release guide

README.md

@@ -12,6 +12,25 @@ This repository contains the web frontend for the ProvideQ toolbox.
    You can disable the data collection using `yarn exec next telemetry disable`.
 5. Use `yarn dev` to spin up a local development server
 
+## Releasing a new version
+1. Create a release branch from develop: `git checkout -b release/x.y.z`.
+2. Bump the version number in the `package.json` file to the new version number
+   and commit it to the release branch.
+3. Push to GitHub and create a pull request to merge the release branch into
+   `main`.
+4. Make sure to test your new version!
+5. Write a changelog.
+   The PR can help you identify differences between the last release (`main`)
+   and the next one (your release branch).
+6. Tag the release commit with your version number and attach the changelog as
+   its message: `git tag -a x.y.z`
+7. Merge the PR into main.
+8. Push your new tag (`git push --tags`) and create a new GitHub release from
+   it: https://github.com/ProvideQ/toolbox-server/releases
+9. Pull the main branch (`git checkout main && git pull`), merge it into the
+   develop branch (`git checkout develop && git pull && git merge main`) and
+   push it (`git push`).
+
 ## License
 Copyright (c) 2022 ProvideQ