demobank-ui: improve README

packages/demobank-ui/README.md

@@ -4,8 +4,18 @@
 
 - `pnpm install`: Installs dependencies
 
-- `pnpm run build`: Production-ready build
+- `pnpm run build`: Create a roduction-ready build under `dist/`.
 
 - `pnpm run check`: Run type checker
 
 - `pnpm run lint`: Pass TypeScript files using ESLint
+
+## Testing
+
+By default, the demobank-ui points to `https://bank.demo.taler.net/demobanks/default/`
+as the bank access API base URL.
+
+This can be changed for testing by setting the URL via local storage (via your browser's devtools):
+```
+localStorage.setItem("bank-base-url", OTHER_URL);
+```