add .env.example to frontend and php container and update README.md

docker-compose.yml

@@ -20,6 +20,7 @@ services:
       - "host.docker.internal:host-gateway"
     volumes:
       - app-code:/var/www/app
+      - ./docker/php/.env:/tmp/app.env:ro
     environment:
       - GIT_TOKEN=${GIT_TOKEN}
       - BACKEND_GIT_REPO=${BACKEND_GIT_REPO}
@@ -45,8 +46,10 @@ services:
       - FRONTEND_GIT_BRANCH=${FRONTEND_GIT_BRANCH}
     volumes:
       - app-code:/var/www/app
+      - ./docker/frontend/.env:/tmp/app.env:ro
     depends_on:
-      - php
+      php:
+        condition: service_healthy
     restart: "no"
 
   nginx: