mostly seems to be working!

admin/Dockerfile

@@ -2,6 +2,13 @@
 FROM node:13.12.0-alpine as build
 WORKDIR /app
 ENV PATH /app/node_modules/.bin:$PATH
+ARG REACT_APP_BACKEND_SERVER
+ARG REACT_APP_ADMIN_SERVER
+ARG REACT_APP_ACCOUNT_SERVER
+ARG REACT_APP_FRONTEND_SERVER
+ARG REACT_APP_SITE_NAME
+ARG REACT_APP_ADMIN_EMAIL
+ARG NODE_ENV
 COPY package.json ./
 RUN npm install
 RUN npm install react-scripts@3.4.1 -g --silent