Expanded the help note about default_target_path

Author: javiereguiluz

app/config/security.yml

@@ -32,7 +32,9 @@ security:
                 # Secure the login form against CSRF
                 # Reference: http://symfony.com/doc/current/cookbook/security/csrf_in_login_form.html
                 csrf_token_generator: security.csrf.token_manager
-                # Redirect to post index page after login (by default)
+                # After login, users are redirected by default to their previous page. This
+                # value is only used when the referrer page does not exist (e.g. when
+                # accessing directly to the login page)
                 default_target_path: blog_index
 
             logout: