Missing -z option so brakeman returns non-zero

* Most important part of this fix.
* Otherwise, brakeman reports errors AND there is no CI failure!

Author: justin808

Diff for: lib/tasks/ci.rake

@@ -9,7 +9,7 @@ if Rails.env.development?
   task :security_audit do
     puts Rainbow("Running security audit on code (brakeman)").green
 
-    sh "brakeman --exit-on-warn --quiet -A"
+    sh "brakeman --exit-on-warn --quiet -A -z"
   end
 
   namespace :ci do