Hi Nexmettin,
You need Javascript to add it to the header of the page, as reactive web apps are SPAs. Not sure if google picks it up. Another alternative would be to create a robots.txt file in your root, using a traditional web app and the SEO Friendly URLs feature.
If your pages are not anonymous I don't think you need any of that, as they wont be crawled.
Cheers,
Tiago Simões