Fix Dockerfile for Astro SSR

Dockerfile

@@ -5,7 +5,12 @@ RUN npm install
 COPY . .
 RUN npm run build
 
-FROM nginx:alpine
-COPY --from=builder /app/dist /usr/share/nginx/html
-COPY nginx.conf /etc/nginx/conf.d/default.conf
-EXPOSE 80
+FROM node:20-alpine
+WORKDIR /app
+COPY --from=builder /app/dist ./dist
+COPY --from=builder /app/node_modules ./node_modules
+COPY --from=builder /app/package.json ./
+ENV HOST=0.0.0.0
+ENV PORT=4321
+EXPOSE 4321
+CMD ["node", "dist/server/entry.mjs"]