An error in the controller is showing up when accessing the API without supplying any credentials for HTTP auth.

$ curl -s -H 'Accept: application/json' http://0.0.0.0:3000/api/hosts | json_reformat 
{
    "error": {
        "message": "undefined method `user' for nil:NilClass" 
    }
}

Started GET "/api/hosts" for 127.0.0.1 at 2013-09-04 20:47:42 +0100
Processing by Api::V1::HostsController#index as JSON
undefined method `user' for nil:NilClass (NoMethodError)
/home/dcleal/code/foreman/foreman/app/controllers/api/base_controller.rb:81:in `authorize'