tweaked the README file (closes #351)

Author: fabpot

README.md

@@ -98,9 +98,9 @@ playing with it, you can remove it by following these steps:
 
   * remove the `web/bundles/acmedemo` directory;
 
-  * remove the inclusion of the security configuration in
-    `app/config/config.yml` (remove the `- { resource: security.yml }` line)
-    or tweak the security configuration to fit your needs.
+  * remove the `security.providers`, `security.firewall.login` and
+    `security.firewall.secured_area` entries in the `security.yml` file or
+    tweak the security configuration to fit your needs.
 
 What's inside?
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