README.md in tcr-0.1.2 vs README.md in tcr-0.1.3

@@ -65,9 +65,29 @@
 TCR.turned_off do
   tcp_socket = TCPSocket.open("smtp.mandrillapp.com", 2525)
 end
 ```
 
+To make sure all external calls really happened use `hit_all` option:
+
+```ruby
+class TCRTest < Test::Unit::TestCase
+  def test_example_dot_com
+    TCR.use_cassette('mandrill_smtp', hit_all: true) do
+      # There are previously recorded external calls.
+      # ExtraSessionsError will be raised as a result.
+    end
+  end
+end
+```
+
+You can also use the configuration option:
+
+```ruby
+TCR.configure do |c|
+  c.hit_all = true
+end
+```
 ## Contributing
 
 1. Fork it
 2. Create your feature branch (`git checkout -b my-new-feature`)
 3. Commit your changes (`git commit -am 'Add some feature'`)