title: How to add express backend to existing react app
body: <p>My question is pretty much all in the title.</p>
  
  <p>So I have built a react/redux frontend.
  Now, the task is for it to be served with fresh Express installation.</p>
  
  <p>Say, my api should be served from "/api/...", and react frontend should be at "/"</p>
  
  <p>Is it just a matter of merging node-modules into one and configuring Express routes, or there is something else that needs to be done?</p>