Structure of file:
.env.local
Fill it with google firebase parameters
REACT_APP_ROOT=
REACT_APP_FIREBASE_API_KEY=
REACT_APP_FIREBASE_AUTH_DOMAIN=
REACT_APP_FIREBASE_DATABASE_URL=
REACT_APP_FIREBASE_PROJECT_ID=
REACT_APP_FIREBASE_STORAGE_BUCKET=
REACT_APP_FIREBASE_MESSAGING_SENDER_ID=
REACT_APP_FIREBASE_APP_ID=