added docker build

.github/workflows/docker.yml

@@ -0,0 +1,66 @@
+---
+name: Docker Builds
+
+# Controls when the workflow will run
+on:
+  workflow_dispatch:
+  push:
+    branches:
+      - main
+    tags:
+      - 'v*.*.*'
+
+permissions:
+  contents: read
+  packages: write
+
+# A workflow run is made up of one or more jobs that can run sequentially or in parallel
+jobs:
+  build-dns-gateway:
+    runs-on: ubuntu-latest
+    steps:
+      # Get the repositery's code
+      - name: Checkout
+        uses: actions/checkout@v3
+
+      # https://github.com/docker/setup-qemu-action
+      - name: Set up QEMU
+        uses: docker/setup-qemu-action@v2
+
+      # https://github.com/docker/setup-buildx-action
+      - name: Set up Docker Buildx
+        id: buildx
+        uses: docker/setup-buildx-action@v2
+
+      - name: Login to GHCR
+        if: github.event_name != 'pull_request'
+        uses: docker/login-action@v2
+        with:
+          registry: ghcr.io
+          username: ${{ github.repository_owner }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Docker meta
+        id: meta_dns-gateway
+        uses: docker/metadata-action@v4
+        with:
+          # list of Docker images to use as base name for tags
+          images: |
+            ghcr.io/buglloc/dns-gateway
+          # generate Docker tags based on the following events/attributes
+          tags: |
+            type=schedule
+            type=ref,event=branch
+            type=semver,pattern={{version}}
+            type=semver,pattern={{major}}.{{minor}}
+            type=semver,pattern={{major}}
+            type=sha
+
+      - name: Build and push
+        uses: docker/build-push-action@v3
+        with:
+          context: .
+          platforms: linux/amd64,linux/arm64/v8
+          push: ${{ github.event_name != 'pull_request' }}
+          tags: ${{ steps.meta_dns-gateway.outputs.tags }}
+          labels: ${{ steps.meta_dns-gateway.outputs.labels }}