Commands used:
docker run --rm -it -p 5000:5000 example-frontend:1.14
docker run --rm -it -p 8080:8080 example-backend:1.14

Dockerfile for frontend:
FROM node:16.19
EXPOSE 5000
WORKDIR /usr/src/app
COPY package*.json ./
COPY . .
ENV REACT_APP_BACKEND_URL=http://devops:8080
RUN npm install && npm run build
RUN npm install -g serve
CMD ["serve", "-s", "-l", "5000", "build"]


Dockerfile for backend:
FROM golang:1.16
EXPOSE 8080
WORKDIR /usr/src/app
COPY . .
ENV REQUEST_ORIGIN=http://devops:5000
RUN go build
CMD ["./server"]