Add workflow for docker push

.github/workflows/build_n_push.yml

@@ -0,0 +1,45 @@
+name: "Build and push"
+
+on:
+  push:
+    branches:
+      - "master"
+  workflow_dispatch:
+
+jobs:
+  build_n_push:
+    name: Build and push
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v2
+
+      - name: Docker metadata
+        id: meta
+        uses: docker/metadata-action@v3
+        with:
+          images: jsondoe9/metube
+          tags: |
+            type=sha,prefix=sha-,format=short
+            type=raw,value=latest,enable=true
+
+      - name: Set up QEMU
+        uses: docker/setup-qemu-action@v1
+
+      - 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 and push
+        uses: docker/build-push-action@v2
+        with:
+          context: .
+          platforms: linux/amd64,linux/arm64,linux/arm/v7
+          push: true
+          tags: ${{ steps.meta.outputs.tags }}
+          labels: ${{ steps.meta.outputs.labels }}