add dockerfile and github actions workflow for deploy

.github/workflows/deploy.yml

@@ -0,0 +1,38 @@
+name: Deploy to DigitalOcean
+
+on:
+  push:
+    branches:
+      - master
+
+jobs:
+  build-and-deploy:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v2
+
+      - name: Log in to Docker Hub
+        uses: docker/login-action@v1
+        with:
+          username: ${{ secrets.DOCKER_USERNAME }}
+          password: ${{ secrets.DOCKER_PASSWORD }}
+
+      - name: Build and push Docker image
+        uses: docker/build-push-action@v2
+        with:
+          push: true
+          tags: ershisan99/flashcards:latest
+
+      - name: SSH and Deploy to Droplet
+        uses: appleboy/ssh-action@master
+        with:
+          host: ${{ secrets.DROPLET_IP }}
+          username: root
+          password: ${{ secrets.SSH_PASSWORD }}  # Using password instead of key
+          script: |
+            docker pull ershisan99/flashcards:latest
+            docker stop flashcards || true
+            docker rm flashcards || true
+            docker run -d --name flashcards -p 80:3333 ershisan99/flashcards:latest