Merge branch 'nmezzopera-add-frontend-production-faq' into 'master'

Docs: steps to run frontend in production mode locally

See merge request gitlab-org/gitlab!35016

doc/development/fe_guide/frontend_faq.md

@@ -146,3 +146,20 @@ export const fetchFoos = ({ state }) => {
   return axios.get(state.settings.fooPath);
 };
 ```
+
+### 7. How can I test the production build locally?
+
+Sometimes it's necessary to test locally what the frontend production build would produce, to do so the steps are:
+
+1. Stop webpack: `gdk stop webpack`.
+1. Open `gitlab.yaml` located in your `gitlab` installation folder, scroll down to the `webpack` section and change `dev_server` to `enabled: false`.
+1. Run `yarn webpack-prod && gdk restart rails-web`.
+
+The production build takes a few minutes to be completed; any code change at this point will be
+displayed only after executing the item 3 above again.
+To return to the normal development mode:
+
+1. Open `gitlab.yaml` located in your `gitlab` installation folder, scroll down to the `webpack` section and change back `dev_server` to `enabled: true`.
+1. Run `yarn clean` to remove the production assets and free some space (optional).
+1. Start webpack again: `gdk start webpack`.
+1. Restart GDK: `gdk-restart rails-web`.