Update README adding explaination for using app_host to call remote web servers

README.rdoc

@@ -280,6 +280,19 @@ examples. Just load the dsl and include it anywhere:
     end
     click_link 'Sign in'
 
+== Calling remote servers
+
+Normally Capybara expects to be testing an in-process Rack application, but you can also use it to talk to a web server running anywhere on the internets, by setting app_host:
+
+    require 'capybara'
+    require 'capybara/dsl'
+
+    include Capybara
+    Capybara.current_driver = :selenium
+    Capybara.app_host = 'http://www.google.com'
+
+    visit('/')
+
 == Using the sessions manually
 
 For ultimate control, you can instantiate and use a session manually.