Log into Docker before pushing

.github/workflows/ci.yml

@@ -8,11 +8,25 @@ on:
 jobs:
   build:
     runs-on: ubuntu-24.04
-    env:
-      DOCKER_REPOSITORY: 'instedd/ruby'
-      DOCKER_USER: ${{ secrets.DOCKER_USER }}
-      DOCKER_PASS: ${{ secrets.DOCKER_PASS }}
     steps:
       - uses: actions/checkout@v3
-      - run: |
-          cd ruby-1.9 && docker build -t instedd/ruby:1.9 . && docker push instedd/ruby:1.9
+      -
+        name: Set up QEMU
+        uses: docker/setup-qemu-action@v3
+      -
+        name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v3
+      -
+        name: Login to Docker Hub
+        uses: docker/login-action@v3
+        with:
+          username: ${{ secrets.DOCKER_USER }}
+          password: ${{ secrets.DOCKER_PASS }}
+      -
+        name: Build and push
+        uses: docker/build-push-action@v6
+        with:
+          push: true
+          tags: instedd/ruby:1.9
+          platforms: linux/amd64,linux/arm64
+          context: "{{defaultContext}}:ruby-1.9"