Reuse the API entrypoint from .env (#805)

* Reuse the API entrypoint from .env

* Added a comment

Author: comxd

admin/authentication-support.md

@@ -64,7 +64,7 @@ import { HydraAdmin, hydraClient, fetchHydra as baseFetchHydra } from '@api-plat
 import authProvider from './authProvider';
 import { Route, Redirect } from 'react-router-dom';
 
-const entrypoint = 'https://demo.api-platform.com'; // Change this by your own entrypoint
+const entrypoint = process.env.REACT_APP_API_ENTRYPOINT; // Change this by your own entrypoint if you're not using API Platform distribution
 const fetchHeaders = {'Authorization': `Bearer ${localStorage.getItem('token')}`};
 const fetchHydra = (url, options = {}) => baseFetchHydra(url, {
     ...options,