Improved the sentence

alvarezmario · alvarezmario · commit 1c2abab4783f · 2014-03-27T11:52:00.000-04:00
diff --git a/book/security.rst b/book/security.rst
@@ -20,8 +20,8 @@ perform a certain action.
 .. image:: /images/book/security_authentication_authorization.png
    :align: center
 
-Since the best way to learn is to see an example, let's start by securing your
-application with HTTP Basic authentication.
+Since the best way to learn is to see an example, just imagine that you want
+to secure your application with HTTP Basic authentication.
 
 .. note::
 
