add configuration to use react-java-mysql sample with Docker Dev Environments feature

Signed-off-by: Guillaume Lours <guillaume.lours@docker.com>

react-java-mysql/frontend/Dockerfile

@@ -1,4 +1,6 @@
-FROM node:lts AS development
+# syntax=docker/dockerfile:1.4
+
+FROM --platform=$BUILDPLATFORM node:lts AS development
 
 WORKDIR /code
 COPY package.json /code/package.json
@@ -12,9 +14,24 @@ ENV PORT=3000
 
 CMD [ "npm", "start" ]
 
+FROM development AS dev-envs
+RUN <<EOF
+apt-get update
+apt-get install -y git
+EOF
+
+RUN <<EOF
+useradd -s /bin/bash -m vscode
+groupadd docker
+usermod -aG docker vscode
+EOF
+# install Docker tools (cli, buildx, compose)
+COPY --from=gloursdocker/docker / /
+CMD [ "npm", "start" ]
+
 FROM development AS build
 
-RUN npm run build
+RUN ["npm", "run", "build"]
 
 FROM nginx:1.13-alpine