first attempt with docker hub build hooks

hooks/build

@@ -0,0 +1,7 @@
+#!/bin/bash
+# hooks/build
+# $DOCKER_REPO var is injected into the build environment
+
+docker build --target kopano-core -t ${DOCKER_REPO}:latest-core .
+docker build --target kopano-full -t ${DOCKER_REPO}:latest .
+docker build --target kopano-debugtools -t ${DOCKER_REPO}:latest-debugtools .

hooks/post_push

@@ -0,0 +1,18 @@
+#!/usr/bin/env bash
+# hooks/post_push
+
+version=$(assets/kopano-webaddr.sh -VV)
+
+_docker_add_tags() {
+	local tag="$1"
+	docker tag $IMAGE_NAME $DOCKER_REPO:$tag
+	docker push $DOCKER_REPO:$tag
+}
+
+if [ "$CACHE_TAG" == "latest" ]; then
+	_docker_add_tags latest-full
+	_docker_add_tags ${version}
+	_docker_add_tags ${version}-full
+else
+	_docker_add_tags ${version}${CACHE_TAG#latest}
+if