Add note on testing build files

Author: chasegiunta

README.md

@@ -55,8 +55,9 @@ You can also run your `dev` & `build` tasks from the GUI to get valuable build s
 
 **NOTE:** During development, _only your assets_ will be served from `localhost:8080` and referenced in the base template. You'll still load your site locally under your normal development domain (mysite.test, etc.). This will also cause a brief unstyled flash on page loads due to JS/CSS assets loading from javascript for development. **This flash isn't present after build, on production**.
 
-For a detailed explanation on how things work, check out the [Vue CLI docs](https://cli.vuejs.org/).
+After running `npm run build`, the easiest way to test your build files locally is to comment the environment variable in your `.env` file, and refresh the page. This will serve your assets from the build directory, rather than webpack's dev server.
 
+For a detailed explanation on how things work, check out the [Vue CLI docs](https://cli.vuejs.org/).
 
 ## Pre-Processors