Add manual testing instructions

guides/browser-support.md

@@ -114,6 +114,37 @@ browsers:
 - iOS Safari
 - Chrome for Android
 
+#### Manual testing
+
+We use a mix of [Sauce Labs](https://saucelabs.com/) and
+[localtunnel](https://localtunnel.github.io/www/) to manually test our site.
+Be sure to review both the
+[testing](https://github.com/cfpb/development/blob/master/guides/testing.md)
+and [accessibility](https://github.com/cfpb/development/blob/master/guides/accessibility.md)
+guides when reviewing sites locally.
+
+##### Sauce Labs
+
+See [#171](https://github.com/cfpb/development/pull/171) for details on testing
+with Sauce Labs.
+
+##### localtunnel
+
+To test changes using your CFPB issued iPhone or other devices, you'll need to
+use localtunnel to expose your localhost. Start by installing localtunnel if
+you haven't already.
+
+```bash
+npm install -g localtunnel
+```
+
+Start your project's localhost and in a separate tab run `lt --port 8000`
+editing the port value to match your localhost setup. This will create a
+temporary public URL that can be accessed from any device on any connection.
+Navigate to the URL from your device and test to your heart's content, the URL
+will remain active as long as the instance is active (keep this in mind, don't
+leave it running forever). Use `ctr + c` to terminate the connection.
+
 #### Individual projects to test
 
 - [cfgov-refresh](https://github.com/cfpb/cfgov-refresh/blob/master/CONTRIBUTING.md#browser-support)