title: why react should usually be a prod dependency and not dev-dependency
body: <p>Sorry if I'm missing some obvious thing, but I can't seem to understand why react (or react-dom) should be a dependency and not dev-dependency on most projects..
  Usually the src is written in es6 and stored in /src or /client for example, and when someone want to build the project for prod he will create /build or /dist where the finalize bundle.js will seat (using webpack and such). from there (at prod) it simply a web server which serve regular js (the bundle) and html file.</p>
  
  <p>Do I miss somthing?</p>
  
  <p>I dont understand why will I want react on the prod (unless going for SSR of course)..</p>
  
  <p>Thank you very much!</p>