title: docker build not setting up environment variables using ENV
body: <p>Trying to build a docker image with golang and react code. The environment variable JWT_SECRET_KEY is not being set.</p>
  <pre><code># Build the Go API
  FROM golang:latest AS builder
  ADD . /app
  WORKDIR /app/server
  ENV JWT_SECRET_KEY=DefaultKey
  RUN go mod download
  RUN CGO_ENABLED=0 GOOS=linux GOARCH=amd64 go build -ldflags &quot;-w&quot; -a -o /main .
  
  # Build the React application
  FROM node:alpine AS node_builder
  COPY --from=builder /app/client ./
  RUN npm install
  RUN npm run build
  
  # Final stage build, this will be the container
  # that we will deploy to production
  FROM alpine:latest
  RUN apk --no-cache add ca-certificates
  COPY --from=builder /main ./
  COPY --from=node_builder /build ./web
  RUN chmod +x ./main
  EXPOSE 8080
  CMD ./main
  </code></pre>
  <p>To build this i ran the command</p>
  <pre><code>docker build -t webapp .
  </code></pre>