added N as a possible base in pileup #74

	---
	name: build-image

	on:
	push:
	jobs:
	build:
	runs-on: ubuntu-latest
	env:
	GH_REPO: c3genomics/ncov-tools
	steps:
	- name: Set up Docker Buildx
	uses: docker/setup-buildx-action@v1
	- name: Login to DockerHub
	uses: docker/login-action@v1
	with:
	username: ${{ secrets.DOCKERHUB_USERNAME }}
	password: ${{ secrets.DOCKERHUB_TOKEN }}
	- name: Build on all branch
	id: alpha
	uses: docker/build-push-action@v2
	with:
	push: true
	tags: ${{ env.GH_REPO }}:alpha
	cache-from: type=registry,ref=${{ env.GH_REPO }}:alpha
	cache-to: type=inline
	-
	name: Docker meta
	id: docker_meta
	uses: crazy-max/ghaction-docker-meta@v1
	with:
	images: ${{ env.GH_REPO }} # list of Docker images to use as base name for tags
	tag-sha: true # add git short SHA as Docker tag
	- name: push latest
	if: ${{ github.ref == 'ref/head/master' }}
	id: latest
	uses: docker/build-push-action@v2
	with:
	push: true
	tags: ${{ env.GH_REPO }}:latest
	cache-from: type=registry,ref=${{ env.GH_REPO }}:alpha
	cache-to: type=inline
	- name: push tag
	if: contains(github.ref, 'tags/v')
	id: tag
	uses: docker/build-push-action@v2
	with:
	push: true
	cache-from: type=registry,ref=${{ env.GH_REPO }}:alpha
	cache-to: type=inline
	tags: ${{ steps.docker_meta.outputs.tags }}
	labels: ${{ steps.docker_meta.outputs.labels }}

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