Update README.md

Author: lovasoa

README.md

@@ -6,6 +6,8 @@ The only differences with a traditional create-react-app application are :
  - The usage of [react-app-rewired](https://www.npmjs.com/package/react-app-rewired) to allow providing a custom [webpack](https://webpack.js.org/) configuration
  - a custom [`config-overrides.js`](./config-overrides.js) to copy the wasm module from sql.js to the distributed assets
 
+ Note that you should make sure your server serves `.wasm` files with the right mimetype, that is: `application/wasm`. Otherwise, you'll see the following warning in the console: `TypeError: Response has unsupported MIME type`
+ 
  See [`src/App.js`](./src/App.js) for the code.
 
  ### [view the live demo](https://sqljs-react-demo.netlify.com/)