Document: Not documented yet on how to build Docker image.

[cloudwindy]

Document: Not documented yet on how to build Docker image.

[initdc]

https://github.com/initdc/ssh-proxy-by-caddy-l4

[kslr]

see

docker/.github/workflows/docker-push.yml

Lines 55 to 70 in efaa50e

	- name: Prepare environment variables
	id: prepare
	run: |
	echo ::set-output name=docker_platforms::linux/386,linux/amd64,linux/arm/v6,linux/arm/v7,linux/arm64
	echo ::set-output name=docker_image::v2fly/v2fly-core
	echo ::set-output name=docker_tag::${{ steps.tag.outputs.tag }}
	echo ::set-output name=docker_is_push::${PUSH:-false}
	- name: Build tag & latest release
	run: |
	docker buildx build --platform ${{ steps.prepare.outputs.docker_platforms }} \
	--output "type=image,push=${{ steps.prepare.outputs.docker_is_push }}" \
	--tag "${{ steps.prepare.outputs.docker_image }}:${{ steps.prepare.outputs.docker_tag }}" \
	--tag "${{ steps.prepare.outputs.docker_image }}:latest" \
	--build-arg TAG=${{ steps.prepare.outputs.docker_tag }} \
	--file Dockerfile .