Clarify the release operations (#6)

Author: nakamura-to

RELEASE_OPERATIONS.md

@@ -0,0 +1,82 @@
+# Release Operations
+
+## Set the release version
+
+Run the Maven `version:set` goal:
+
+```
+$ git checkout master
+$ git pull
+$ ./mvnw versions:set
+```
+
+After success, run the Maven `version:commit` goal:
+
+```
+$ ./mvnw versions:commit
+```
+
+Commit the release version:
+
+```
+$ git commit -m "Release v1.0.0"
+```
+
+## Push to the master branch
+
+Create a tag and push the commit and the tag:
+
+```
+$ git tag -a v1.0.0 -m "v1.0.0"
+$ git push origin master --tags
+```
+
+## Build with GitHub Action
+
+The GitHub Action workflow [Java CI with Maven](.github/workflows/ci.yml) handles the above push event.
+
+The workflow builds the "doma-quarkus-parent", the "doma-quarkus-deployment" and the "doma-quarkus" artifacts
+and pushes them to Maven Central[Sonatype OSSRH](https://central.sonatype.org/pages/ossrh-guide.html).
+
+## Publish artifacts to Maven Central from Sonatype OSSRH
+
+Follow the instructions below:
+
+- Open [Nexus Repository Manager](https://oss.sonatype.org/).
+- Log in to the manager.
+- Select "Staging Repositories" from the side menu.
+- Check the repository of Doma.
+- Push the "Release" button.
+
+In a few minutes, all artifacts are copied to the [Maven Central Repository](https://repo1.maven.org/).
+
+## Publish release notes
+
+Open [Releases](https://github.com/domaframework/doma-quarkus/releases)
+and publish release notes.
+
+## Announce the release
+
+Announce the release of new version using Twitter.
+- [@domaframework](https://twitter.com/domaframework)
+
+## Set the next version
+
+Run the Maven `version:set` goal:
+
+```
+$ ./mvnw versions:set
+```
+
+After success, run the Maven `version:commit` goal:
+
+```
+$ ./mvnw versions:commit
+```
+
+Commit and push the next version:
+
+```
+$ git commit -m "Next version [skip ci]"
+$ git push origin master
+```