Update README.md #13

	name: publish
	on:
	push:
	branches: [ main ]

	jobs:
	publish-ping-image:
	runs-on: ubuntu-latest

	steps:
	- uses: actions/checkout@v2

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

	- name: Extract branch name
	shell: bash
	run: echo "##[set-output name=branch;]$(echo ${GITHUB_REF#refs/heads/})"
	id: extract_branch

	- name: Build Docker image
	run: \|
	docker build . --tag ghcr.io/redline-hosting/ping:${{ steps.extract_branch.outputs.branch }}
	docker push ghcr.io/redline-hosting/ping:${{ steps.extract_branch.outputs.branch }}

Provide feedback