add: GitHub workflow

.github/workflows/main.yml

@@ -0,0 +1,18 @@
+name: Deploy
+on: [push]
+jobs:
+  build:
+    name: Build
+    runs-on: ubuntu-latest
+    steps:
+      - name: Deploy the backend
+        uses: appleboy/ssh-action@v1
+        with:
+          host: ${{ secrets.HOST }}
+          username: ${{ secrets.USERNAME }}
+          password: ${{ secrets.PASSWORD }}
+          port: ${{ secrets.PORT }}
+          script: |
+            cd /web/cvsa
+            git pull
+            pm2 restart cvsa-be --update-env