update read me with steps to create new release image

Signed-off-by: Roshan Khatri <[email protected]>

README.md

@@ -3,3 +3,12 @@ This Project is the Git repo of the [Valkey "Official Image"](https://hub.docker
 The Project is now maintained by [the Valkey Community](https://github.com/valkey-io/valkey/) 
 and it was forked from https://github.com/docker-library/redis.
 
+## How to build and publish new version Docker Image?
+*Pre-requisites: Fork this repo, create a private dockerhup repo and setup the Github secrets to access the private dockerhup repo.*
+1. Validate if the metadata for the new version is updated at https://github.com/valkey-io/valkey-hashes/blob/main/README
+2. If its a new major version create a new dir. For example `7.2`.
+3. Run the `update.sh` script locally, which will update the `versions.json` and also populate the Dockerfiles for the new versions in the repective directories.
+4. Validate if the version and the info is populated correctly.
+5. See if all the tests pass on your fork and the your private docker up has been updated. 
+5. Publish a PR with these changes. For example: https://github.com/valkey-io/valkey-container/pull/8
+6. Once the PR is merged, Sit back, relax and enjoy looking at your creation getting publish to the official Docker hub page. 

temp.sh

@@ -0,0 +1,10 @@
+#!/bin/bash
+
+original_tags='[
+  valkey-container:unstable,
+  valkey-container:unstable-bookworm
+]'
+
+converted_list=$(echo $original_tags | sed 's/valkey-container/valkey\/valkey/g'| sed 's/\[ *//; s/ *\]//; s/ //g')
+echo $converted_list
+