Create docker-image.yml

Added configuration to automatically trigger multi-platform docker builds via github actions

.github/workflows/docker-image.yml

@@ -0,0 +1,30 @@
+name: Build and Push Docker Image
+
+on:
+  push:
+    branches:
+      - master
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v2
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v2
+
+      - name: Log in to DockerHub
+        uses: docker/login-action@v2
+        with:
+          username: ${{ secrets.DOCKERHUB_USERNAME }}
+          password: ${{ secrets.DOCKERHUB_TOKEN }}
+
+      - name: Build and push multi-architecture image
+        run: |
+          docker buildx build --platform linux/amd64,linux/arm/v7,linux/arm64 -t iitgdocker/iperf-web:latest --push .
+
+        env:
+          DOCKER_CLI_EXPERIMENTAL: enabled
+          DOCKER_BUILDKIT: 1