feat: add Dockerfile

Dockerfile

+# build stage
+FROM node:12-alpine as build-stage
+WORKDIR /app
+COPY package*.json ./
+RUN npm config set sass_binary_site https://npm.taobao.org/mirrors/node-sass -g && npm config set registry https://registry.npm.taobao.org
+RUN npm install
+COPY . .
+RUN npm run build
+
+# production stage
+FROM nginx:stable-alpine as production-stage
+COPY --from=build-stage /app/dist /usr/share/nginx/html
+EXPOSE 80
+CMD ["nginx", "-g", "daemon off;"]