Added links to React.js documentation for hello_react
Added links to React.js documentation for hello_react

marocchino/learnyoureact,tako-black/learnyoureact,aksharpatel47/learnyoureact,hvp/learnyoureact,thebuilder/learnyoureact,kohei-takata/learnyoureact,workshopper/learnyoureact,vbdoug/learnyoureact,timguoqk/learnyoureact,Mavmeister/learnyoureact