Add deployment workflow

.github/workflows/deploy.yaml

@@ -0,0 +1,51 @@
+name: Build and deploy
+on:
+  push:
+    branches:
+      - "master"
+
+jobs:
+  build:
+    name: Build container image
+    runs-on: ubuntu-latest
+    permissions:
+      packages: write
+    steps:
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v2
+
+      - name: Docker meta
+        id: meta
+        uses: docker/metadata-action@v4
+        with:
+          images: ghcr.io/cog-creators/cog-browser
+          flavor: |
+            latest=true
+          tags: |
+            type=sha
+
+      - name: Login to GitHub Container Registry
+        if: github.repository_owner == 'cog-creators'
+        uses: docker/login-action@v2
+        with:
+          registry: ghcr.io
+          username: ${{ github.repository_owner }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Build and push image
+        uses: docker/build-push-action@v4
+        with:
+          push: ${{ github.repository_owner == 'cog-creators' }}
+          platforms: linux/amd64
+          tags: ${{ steps.meta.outputs.tags }}
+
+  deploy:
+    name: Deploy to index.discord.red
+    needs: build
+    environment: Deployment
+    runs-on: ubuntu-latest
+    if: ${{ github.repository_owner == 'cog-creators' }}
+    steps:
+      - name: Trigger deployment.
+        run: >-
+          curl -H "X-Token: ${{ secrets.WEBHOOK_DEPLOY_INDEX_TOKEN }}" "${{ secrets.WEBHOOK_DEPLOY_INDEX_URL }}"