Add CI pipeline #4

	name: Prebuild Database Images

	on:
	pull_request:
	branches:
	- main

	jobs:
	build:
	runs-on: ubuntu-latest

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

	- name: Log in to GitHub Container Registry
	uses: docker/login-action@v2
	with:
	registry: ghcr.io
	username: ${{ github.actor }}
	password: ${{ secrets.GITHUB_TOKEN }}

	- name: Calculate SHA256 for postgres_primary.dockerfile
	id: primary_sha
	run: echo "::set-output name=sha256::$(sha256sum postgres_primary.dockerfile \| awk '{ print substr($1, 1, 12) }')"

	- name: Calculate SHA256 for postgres_replica.dockerfile
	id: replica_sha
	run: echo "::set-output name=sha256::$(sha256sum postgres_replica.dockerfile \| awk '{ print substr($1, 1, 12) }')"

	- name: Compute container registry name
	run: echo "CR_NAME::$(echo ghcr.io/${{ github.repository }} \| tr '[:upper:]' '[:lower:]')" >> $GITHUB_ENV

	- name: Build and tag primary Docker image
	run: docker build -f postgres_primary.dockerfile -t $CR_NAME/postgres_primary:${{ steps.primary_sha.outputs.sha256 }} .

	- name: Build and tag replica Docker image
	run: docker build -f postgres_replica.dockerfile -t $CR_NAME/postgres_replica:${{ steps.replica_sha.outputs.sha256 }} .

	- name: Push primary Docker image
	run: docker push $CR_NAME/postgres_primary:${{ steps.primary_sha.outputs.sha256 }}

	- name: Push replica Docker image
	run: docker push $CR_NAME/postgres_replica:${{ steps.replica_sha.outputs.sha256 }}

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