Fixing Dockerfile.prod Fixes #61 (#63)

Dockerfile.prod

@@ -1,8 +1,6 @@
 FROM node:13.12.0-alpine as build
 WORKDIR /app
 ENV PATH /app/node_modules/.bin:$PATH
-ARG BASE_URL
-ENV REACT_APP_BASE_URL $BASE_URL
 COPY ./package.json ./package-lock.json /app/
 RUN npm ci --silent
 RUN npm install [email protected] -g --silent
@@ -13,4 +11,4 @@ FROM nginx:stable-alpine
 COPY --from=build /app/build /usr/share/nginx/html
 COPY nginx/nginx.conf /etc/nginx/conf.d/default.conf
 EXPOSE 80
-CMD ["nginx", "-g", "daemon off;"]
+CMD ["nginx", "-g", "daemon off;"]