Upgrade ruby and migrate to Github actions (#7) #2

	name: Docker

	on:
	push:
	branches:
	- master
	tags:
	- v*

	env:
	IMAGE_NAME: hammady/scaltainer

	jobs:
	docker:
	runs-on: ubuntu-latest
	if: github.event_name == 'push'

	steps:
	- name: Checkout
	uses: actions/checkout@v2

	- name: Determine target image name
	id: image-name
	run: \|
	IMAGE_ID=ghcr.io/$IMAGE_NAME

	# Strip git ref prefix from version
	VERSION=$(echo "${{ github.ref }}" \| sed -e 's,./$.$,\1,')

	# Strip "v" prefix from tag name
	[[ "${{ github.ref }}" == "refs/tags/"* ]] && VERSION=$(echo $VERSION \| sed -e 's/^v//')

	# Use Docker `latest` tag convention
	[ "$VERSION" == "master" ] && VERSION=latest

	IMAGES=
	IMAGES="$IMAGE_ID:$VERSION"$'\n'$IMAGES

	# debug output
	echo images $IMAGES
	echo ::set-output name=images::"$IMAGES"

	- name: Set up QEMU
	uses: docker/setup-qemu-action@v1

	- name: Set up Docker Buildx
	uses: docker/setup-buildx-action@v1

	- name: Login to registry
	uses: docker/login-action@v1
	with:
	registry: ghcr.io
	username: ${{ github.actor }}
	password: ${{ secrets.GITHUB_TOKEN }}

	- name: Build and push
	uses: docker/build-push-action@v2
	with:
	context: .
	platforms: linux/amd64,linux/arm64,linux/arm/v7
	push: true
	tags: ${{ steps.image-name.outputs.images }}

Provide feedback