Add fb_helpers cookbook requirement to README.md (#242)
Add fb_helpers cookbook requirement to README.md (#242)

Summary:
On the tin.
Pull Request resolved: https://github.com/facebook/IT-CPE/pull/242

Reviewed By: steelcowboy

Differential Revision: D21529739

Pulled By: michel-slm

fbshipit-source-id: 45db6b63078b0795fc7270c04e3cbb1ec66a71fb

facebook/IT-CPE,facebook/IT-CPE,facebook/IT-CPE