dillon1000/react

'npm init' needed before installing react via npm. (#8649)

* 'npm init' needed before installing react via npm.

I was trying to install react in my django project directory and was getting warnings about package.json not being present. Started this SO post (http://stackoverflow.com/questions/41340909/npm-cant-find-package-json-when-installing-react/41340975#41340975) to figure it out. I think it'll be useful to others too if we add it in the documentation itself.

* Tweak instructions