Add GH action for nginx docker image

.github/workflows/docker-build.yml

@@ -1,4 +1,4 @@
-name: Docker Multi-Architecture Build
+nme: Docker Multi-Architecture Build
 
 on:
   push:
@@ -90,3 +90,44 @@ jobs:
           tags: ytorg/yotter:pypy
           cache-from: type=local,src=cache
           cache-to: type=local,dest=cache
+  nginx-build-docker:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+        with:
+          fetch-depth: 0
+      - name: Set up QEMU
+        uses: docker/setup-qemu-action@v1
+        with:
+          platforms: all
+      - name: Set up Docker Buildx
+        id: buildx
+        uses: docker/setup-buildx-action@v1
+        with:
+          version: latest
+      - name: Login to DockerHub
+        uses: docker/login-action@v1
+        with:
+          username: ${{ secrets.DOCKER_USERNAME }}
+          password: ${{ secrets.DOCKER_PASSWORD }}
+      - name: Get hash of latest image
+        run: docker pull nginx:mainline-alpine && docker inspect --format='{{index .RepoDigests 0}}' nginx:mainline-alpine > dockerhash.txt
+      - name: Write the current version to a file
+        run: "{ git describe --tags --abbrev=0 & date +\"%d-%m-%y\" & git rev-list HEAD --max-count=1 --abbrev-commit;} > version.txt"
+      - name: cache docker cache
+        uses: actions/cache@v2.1.4
+        with:
+          path: ${{ github.workspace }}/cache
+          key: ${{ runner.os }}-docker-nginx-${{ hashFiles('**/dockerhash.txt') }}
+          restore-keys: |
+            ${{ runner.os }}-docker-nginx-
+      - name: Build and push
+        uses: docker/build-push-action@v2
+        with:
+          context: .
+          file: ./Dockerfile
+          platforms: linux/amd64,linux/arm64
+          push: true
+          tags: ytorg/nginx:latest
+          cache-from: type=local,src=cache
+          cache-to: type=local,dest=cache

docker-compose.yml

@@ -13,9 +13,7 @@ services:
     healthcheck:
       test: ["CMD", "mysqladmin", "ping", "--silent"]
   nginx:
-    build:
-      context: .
-      dockerfile: nginx.Dockerfile
+    image: ytorg/nginx:latest
     restart: unless-stopped
     environment:
       HOSTNAME: 'changeme.example.com'