Add CI for deployment

.github/workflows/main.yml

@@ -0,0 +1,17 @@
+on: push
+name: Deploy
+jobs:
+  web-deploy:
+    name: Deploy
+    runs-on: ubuntu-latest
+    steps:
+    - name: Get latest source code
+      uses: actions/checkout@v3
+
+    - name: Sync files
+      uses: SamKirkland/FTP-Deploy-Action@v4.3.4
+      with:
+        server: seznamovak.pedf.cuni.cz
+        username: ${{ secrets.ftp_username }}
+        password: ${{ secrets.ftp_password }}
+        server-dir: www/