Add more detail to the contribution docs

Author: pimterry

README.md

@@ -32,12 +32,13 @@ To get started:
 * `npm install`
 * `npm start`
 * A [Mockttp](https://npmjs.com/package/mockttp) standalone server will start on port 45456, and a graphql management server on 45457.
-* Either make requests to the servers by hand, or start a UI using it by:
+* Either make requests to the servers by hand, use the production UI by opening `https://app.httptoolkit.tech` in a Chromium-based browser, or start and use a local UI by:
     * Setting up the web UI locally (see [httptoolkit/httptoolkit-ui#contributing](https://github.com/httptoolkit/httptoolkit-ui#contributing)).
     * Running `npm run start:web` there to start the UI without its own server.
+    * Opening `http://local.httptoolkit.tech:8080` in a Chromium-based browser
 
 A few tips:
 
 * Running the server with `ENABLE_PLAYGROUND` set to `true` at the top of [`src/api-server.ts`](src/api-server.ts#L16) will give you a GraphQL playground on http://localhost:45457/.
 * New interceptors need to be added to `src/interceptors/index.ts`. They will also need to be added to [the UI](https://github.com/httptoolkit/httptoolkit-ui).
-* The tests assume that the required applications are installed to run every interceptor. See [.travis.yml](.travis.yml) for an example of how to set this up.
+* The tests assume that the required applications are installed to run every interceptor. See [.travis.yml](.travis.yml) for an example of how to set this up.