fix dockerfile

Dockerfile

@@ -1,5 +1,18 @@
-FROM nginx:stable-alpine
+FROM node:15 as build
+
+# https://github.com/jgm/pandoc/releases
+RUN curl -LO https://github.com/jgm/pandoc/releases/download/2.14.0.1/pandoc-2.14.0.1-1-amd64.deb
+RUN dpkg -i pandoc-2.14.0.1-1-amd64.deb
+
+WORKDIR /app
+COPY package.json /app
+RUN yarn install
+COPY themes /app/themes
+COPY source /app/source
+COPY _config.yml /app/
+RUN yarn build
+
+FROM nginx:stable-alpine as runtime
 
 COPY nginx.conf /etc/nginx/nginx.conf
-
-COPY public /var/www/html/
+COPY --from=build /app/public /var/www/html/