$ JWT_SECRET=
$ MONGODB_URI=
$ PAYPAL_CLIENT_ID=
$ CLOUDINARY_CLOUD_NAME=
$ CLOUDINARY_API_KEY=
$ CLOUDINARY_API_SECRET=
$ GOOGLE_API_KEY=
$ MAILGUN_DOMIAN=
$ MAILGUN_API_KEY=
$ cd backend
$ npm install
$ npm start
# open new terminal
$ cd frontend
$ npm install
$ npm start