Updated README with info about multiarch builds and versioned tags

README.md

@@ -5,14 +5,31 @@
 
 Simple Postfix SMTP TLS relay [docker](http://www.docker.com) alpine based image with no local authentication enabled (to be run in a secure LAN).
 
+This image is available for the following architectures:
+
+* 386
+* amd64 (_latest_ and _alpine_ tags)
+* armv6
+* armv7
+* arm64
+
 It also includes rsyslog to enable logging to stdout.
 
 
 _If you want to follow the development of this project check out [my blog](https://www.juanbaptiste.tech/category/postfx)._
 
 ### Available image tags
 
-Currently we only handle a rolling release of new versions so only _latest_ tag is available, but there is [work in progress](https://github.com/juanluisbaptiste/docker-postfix/pull/29) to start releasing versioned images to be able to pin to specific versions in production deployments.
+We use semantic versioning for this image. For all supported architectures there are the following versioned tags:
+
+* Major (1)
+* Minor (1.0)
+* Patch (1.0.0)
+
+Additionally the amd64 architecture has the following tags:
+
+* _latest_
+* _alpine_
 
 *_NOTES_*:
   * The _alpine_ tag has been switched to use the master branch, but it's irrelevant as it is the same as _latest_.