title: ReactJS APP in Heroku "Invalid Host header" HOST configuration?
body: <p>I am trying to put my <a href="https://github.com/gitlwh/MembershipSample/tree/master/client" rel="noreferrer">React app</a> on the Heroku. The whole project include one API (express) and one client (ReactJS). I have put my API on heroku. But when I put my client on Heroku, it shows build succeeded. But when I <a href="https://shielded-temple-31393.herokuapp.com/" rel="noreferrer">open</a> it, it shows <code>Invalid Host header</code>. </p>
  
  <p>I google this problem and many people tell me to configure the <a href="https://github.com/facebook/create-react-app/issues/2271" rel="noreferrer">HOST</a>. But they are using webpack. I build this with <code>create-react-app</code> and I run it by <code>npm start</code>. I want to know how to solve this problem in most easy way. Thanks.</p>