add a basic deploy workflow

.github/workflows/deploy.yml

@@ -0,0 +1,32 @@
+name: "Deploy safe settings app"
+on:
+  push:
+    branches:
+      - main
+
+jobs:
+  deploy:
+    name: Deploy new image
+    environment: prod
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Log in to Azure using OIDC
+        uses: azure/login@v2
+        with:
+          client-id: ${{ secrets.DEPLOY_APP_CLIENT_ID }}
+          tenant-id: ${{ secrets.AZURE_AD_TENANT_ID }}
+          subscription-id: ${{ secrets.AZURE_SUBSCRIPTION_ID }}
+
+      - name: Login to Azure Container Registry
+        run: az acr login --name hsoghacr
+
+      - name: Build docker image
+        run: docker build -t hsoghacr.azurecr.io/safesettings:latest .
+
+      - name: Push image
+        run: docker push hsoghacr.azurecr.io/safesettings:latest
+
+      - name: Restart app to load the new image
+        run: az webapp restart -n hso-gh-config-app -g hso-gh-config