// In main package.json (outside client/ and backend/ folder, add the start:server, start:client, and start:dev as shown below

"test": //... unchanged
"start:server": "cd backend && nodemon server.js --exec babel-node --presets es2015,stage-0",
"start:client": "cd client && yarn start",
"start:dev": "concurrently \"yarn start:server\" \"yarn start:client\""