Update publishing instructions

Author: michaelmcandrew

README.md

@@ -138,6 +138,10 @@ CiviCRM Buildkit Docker is written by [Michael McAndrew](https://twitter.com/mic
 
 Contributions to this repository are very welcome. Feel free to submit a pull request for minor improvements. For larger changes, please create an issue first.
 
+## See also
+
+* [Publishing Dockerfiles](publish/README.md) for details on how to update the image published on https://hub.docker.com.
+
 ## License
 
 This extension is licensed under [AGPL-3.0](LICENSE.txt).

publish/README.md

@@ -21,10 +21,14 @@ civicrm:
 
 ## Updating Dockerfiles
 
-1. Make any necessary changes to the `templates` and `publish.php` script.
-2. From the `publish` directory, `composer install` (if you haven't already) and run `php publish.php`
-3. Check the generated directories in `publish/civicrm`
+1. From the `publish` directory, run `composer install`
+2. Make any necessary changes to the `templates` and `publish.php` script.
+3. Run `php publish.php`
+4. Check the generated directories in `publish/civicrm`
+5. Optionally, copy the contents of `publish/civicrm/php7.0` to `civicrm` with `cp -r publish/civicrm/php7.0/* civicrm`
 
-## Updating the `:latest` (default) Dockerfile
+## Publishing updates to https://hub.docker.com
 
-Copy the contents of `publish/civicrm/php7.0` to `civicrm` with `cp publish/civicrm/php7.0/* civicrm`.
+Lets say you wanted publish the image for the civicrm container you are currently using. `docker ps` will show the list of containers in use. `docker inspect --format='{{.Image}}' $CONTAINER_ID` will give you the appropriate the Image ID.
+
+You can then tag the image id with michaelmcandrew/civicrm like this `docker tag $IMAGE_ID michaelmcandrew/civicrm` and publish it with `docker push michaelmcandrew/civicrm`.