Add RELEASING.md

Author: Taichi Yamakawa

README.md

@@ -66,6 +66,10 @@ For more details, please refer to [Operation Guide](docs/operation_guide.md).
 
 [CONTRIBUTING](CONTRIBUTING.md) may help us.
 
+## For Maintainers
+
+[RELEASING](RELEASING.md) describes how to release a new version.
+
 ## Examples
 
 You can see a sample application using this extension in the following project.

RELEASING.md

@@ -0,0 +1,70 @@
+# Releasing
+
+This document describes how to release a new version `X.Y.Z` for maintainers.
+It would be required to replace `X.Y.Z` with the actual release version.
+
+## 1. Create a new branch
+
+Create a new branch `release/vX.Y.Z` from `master` branch like the following:
+```shell
+git checkout master
+git pull origin
+git checkout -b release/vX.Y.Z
+```
+
+## 2. Update `CHANGELOG.md`
+
+1. Add a section of the new release version `vX.Y.Z`  
+    We recommend you add one of the following links to this section.
+    * `https://github.com/lerna-stack/akka-entity-replication/compare/vA.B.C...vX.Y.Z` if this release is a successor.
+      * `A.B.C` is the previous latest version.
+    * `https://github.com/lerna-stack/akka-entity-replication/tree/vX.Y.Z` if this release is the first one.
+2. Update the unreleased version link to `https://github.com/lerna-stack/akka-entity-replication/compare/vX.Y.Z...master`
+
+## 3. Commit & Push
+
+Commit changes, and then push the branch like the following:
+```shell
+git commit --message 'release vX.Y.Z'
+git push origin
+```
+
+## 4. Create a Pull Request
+
+After committing and pushing all changes, create a pull request.
+Other maintainers will review and merge the pull request.
+
+## 5. Push a new version tag `vX.Y.Z`
+
+*It is highly recommended ensuring that the new version tag is correct.*  
+*The CI will automatically publish this release when detecting the version tag.*
+
+Create and push the new version tag `vX.Y.Z` like the following:
+```shell
+git checkout master
+git tag vX.Y.Z
+git push origin vX.Y.Z
+```
+
+## 6. Check the release is available
+
+Check the release is available at [Maven Central Repository](https://repo1.maven.org/maven2/com/lerna-stack/).
+
+**NOTE**
+- The release will be available about 10 minutes after publishing.
+- It requires more time to be able to find the release with searching (about 2 hours max).
+
+## 7. Create a new release `vX.Y.Z`
+
+Create a new release `vX.Y.Z` from [this link](https://github.com/lerna-stack/akka-entity-replication/releases/new).
+
+- **Choose a tag**: select the new version tag
+- **Release title**: the same as the tag
+- **Describe this release**:  
+    Write the following text, at least.  
+    Replace the part `#vXYZ---YYYY-MM-DD` of the link with the actual release version and date.
+    ```markdown
+    See [CHANGELOG] for details.
+  
+    [CHANGELOG]: https://github.com/lerna-stack/akka-entity-replication/blob/master/CHANGELOG.md#vXYZ---YYYY-MM-DD
+    ```