Push Docker images to GitHub container registry

.github/workflows/docker.yml

@@ -16,16 +16,17 @@ jobs:
         id: docker_tag
         run: |
           SHORT_SHA=`echo ${GITHUB_SHA} | cut -c1-8`
+          APP_VERSION="master.${SHORT_SHA}"
           DOCKER_IMAGE=kanboard/kanboard
           DOCKER_VERSION=dev
-          APP_VERSION="master.${SHORT_SHA}"
           if [ "${{ github.event_name }}" = "schedule" ]; then
           DOCKER_VERSION="nightly"
+          TAGS="${DOCKER_IMAGE}:${DOCKER_VERSION},ghcr.io/${DOCKER_IMAGE}:${DOCKER_VERSION}"
           elif [[ $GITHUB_REF == refs/tags/* ]]; then
-          DOCKER_VERSION=${GITHUB_REF#refs/tags/}
           APP_VERSION=$DOCKER_VERSION
+          DOCKER_VERSION=${GITHUB_REF#refs/tags/}
+          TAGS="${DOCKER_IMAGE}:${DOCKER_VERSION},ghcr.io/${DOCKER_IMAGE}:${DOCKER_VERSION},${DOCKER_IMAGE}:latest,ghcr.io/${DOCKER_IMAGE}:latest"
           fi
-          TAGS="${DOCKER_IMAGE}:${DOCKER_VERSION}"
           echo ::set-output name=version::${APP_VERSION}
           echo ::set-output name=tags::${TAGS}
           echo ::set-output name=created::$(date -u +'%Y-%m-%dT%H:%M:%SZ')
@@ -42,6 +43,13 @@ jobs:
           username: ${{ secrets.DOCKERHUB_USERNAME }}
           password: ${{ secrets.DOCKERHUB_TOKEN }}
 
+      - name: Login to GitHub Container Registry
+        uses: docker/login-action@v1 
+        with:
+          registry: ghcr.io
+          username: ${{ github.repository_owner }}
+          password: ${{ secrets.CR_PAT }}
+
       - name: Build and push
         uses: docker/build-push-action@v2
         with: