Cannot start front end on Linux or Windows WSL

Following https://github.com/Visual-Regression-Tracker/frontend/blob/master/README.md

At the step npm run start on Linux (Ubuntu server) and Windows WSL, the following error is displayed

> vrt-frontend@1.6.0 start
> chmod +x ./env.sh && sh ./env.sh && cp env-config.js ./public/ && react-scripts start

./env.sh: 22: Bad substitution
./env.sh: 24: [[: not found
./env.sh: 22: Bad substitution
./env.sh: 24: [[: not found
./env.sh: 13: [[: not found

It's trying to run dash /bin/dash and the substitution is breaking on Linux and Windows WSL. mac is fine, though.

To fix this, remove the sh from

frontend/package.json

Line 39 in a373f86

"start": "chmod +x ./env.sh && sh ./env.sh && cp env-config.js ./public/ && react-scripts start",

"start": "chmod +x ./env.sh && ./env.sh && cp env-config.js ./public/ && react-scripts start",

Alternatively remove this section from package.json and move it to the readme document

chmod +x ./env.sh && ./env.sh && cp env-config.js ./public/

[paazmaya]

The bash script which creates an environment variable file in JavaScript, should be migrated to be a Node.js script.
This would allow it to be used anywhere.