add configuration to use react-rust-postgres sample with Docker Dev Environments feature (#264)

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

react-rust-postgres/frontend/Dockerfile

@@ -1,3 +1,4 @@
+# syntax=docker/dockerfile:1.4
 FROM node:lts AS development
 
 ENV CI=true
@@ -11,6 +12,21 @@ COPY . /code
 
 CMD [ "npm", "start" ]
 
+FROM development as dev-envs
+RUN <<EOF
+apt-get update
+apt-get install -y --no-install-recommends 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 builder
 
 RUN npm run build