add script for back-side es6 transform to pure js

Add script for transform from ES6 to pureJs on backend
diff --git a/README.md b/README.md
index a29a9d6..0ce67a5 100644
--- a/README.md
+++ b/README.md
@@ -27,6 +27,7 @@
 ```
 npm run setup-backend
 npm run build-front
+npm run build-back
 pm2 stop ag-viewer-develop
 pm2 delete ag-viewer-develop
 pm2 start ecosystem.config.js
diff --git a/package.json b/package.json
index 3bc75c8..b755aba 100644
--- a/package.json
+++ b/package.json
@@ -8,6 +8,7 @@
     "setup-backend": "cd backend && npm install",
     "front": "cd frontend && npm run start",
     "build-front": "cd frontend  && npm install && npm run build",
+    "build-back": "cd backend  && npm install && npm run build",
     "backend": "cd backend && npm run start",
     "deploy": "npm-run-all build-front backend",
     "start": "npm-run-all --parallel backend front"