Add doc for using pkger during development

Author: donatello

README.md

@@ -3,3 +3,34 @@
 ```
 pkger -r RELEASE.2021-01-08T19-38-39Z
 ```
+
+## Packaging minio during development (for testing, etc)
+
+1. First install pkger so it is available in PATH.
+
+2. Prepare the release directory, `dist` below:
+
+```shell
+mkdir -p ./dist/linux-amd64
+
+# REPLACE THE TIMESTAMP AND THE GIT TAG!
+VERSION=RELEASE.2025-03-12T00-00-00Z.debug.GIT_TAG
+
+# Move the binary to the dist directory
+mv ./minio ./dist/linux-amd64/minio.$VERSION
+```
+
+3. Ensure minio.service exists:
+
+```
+wget -O minio.service "https://raw.githubusercontent.com/minio/minio-service/refs/heads/master/linux-systemd/minio.service"
+```
+
+4. Run pkger:
+
+```shell
+# Now run pkger.
+pkger -r $VERSION --appName minio --ignore --releaseDir=dist
+```
+
+5. `./dist will contain the packaged files (rpm, deb, etc).