Undefined method `all' for ActiveSupport in Rails 4.0.0 app -

i'm new developing rails apps, part here, i've relied heavily on rails generate command make scaffolds entire app. while every other part of app works fine, 1 raises error right after being automatically generated.

the error follows:

nomethoderror in configurationscontroller#index  undefined method `all' activesupport::configurable::configuration:class 

here code snippet contains said no method call

def index   @configurations = configuration.all end 

and here said model in question

class configuration < activerecord::base   belongs_to :users, class_name: 'user', foreign_key: 'user_id' end 

i added belongs_to part... anyway, when ran through http://localhost.localhost:3000/users/1/configurations/ error pops up! (yes, used nested routes)

so hit rails console check configuration.all returns , lo , behold

2.0.0-p247 :004 > configuration.all   configuration load (0.3ms)  select "configurations".* "configurations"  => #<activerecord::relation [#<configuration id: 1, user_id: 1, port: 3000, host: "example.org", annoy: 5000, version: "1", machines: nil, created_at: "2013-08-08 02:15:32", updated_at: "2013-08-08 02:15:32">]> 

i'm kind of lost why method works in rails console fails in html view on browser. did wrong?

also, here output on webrick in case looks it

started "/users/1/configurations/" 192.168.1.105 @ 2013-08-08 10:24:59 +0800 processing configurationscontroller#index html   parameters: {"user_id"=>"1"} completed 500 internal server error in 1ms  nomethoderror (undefined method `all' activesupport::configurable::configuration:class):   app/controllers/configurations_controller.rb:8:in `index' 

unfortunately, created class name part of rails api (though in different namespace). class happens @ top-level namespace, while rails class nested in activesupport::configurable namespace. class you'll when reference configuration depends on referencing code located.

to specify want class @ top-level namespace, can refer class ::configuration.

here's simplified test demonstrate what's happening:

# let's module & class defined library (e.g. rails) module configurable  # analogous activesupport::configurable   class configuration  # analogous activesupport::configurable::configuration   end end class controllerbase  # analogous actioncontroller::base   # actioncontroller::base includes activesupport::configurable.   # can confirm in rails 4 returns true:   #   actioncontroller::base.included_modules.include? activesupport::configurable   include configurable end  # class , constant class configuration end  class mycontroller < controllerbase   # analogous code inside controller.   # inheriting gives access constants in parent   def wrong_class     configuration  # oops, wanted top-level   end   def correct_class     ::configuration   end end  # top-level scope p(top_level_access: configuration.name)  # 'configuration' p(nested_access: mycontroller.new.wrong_class.name)  # 'configurable::configuration' p(scoped_nested_access: mycontroller.new.correct_class.name)  # 'configuration' 

edit - reply @maru's comment:

in cases can use configuration.name fully-namespaced name of class. try @ console.

if try rails.logger.info(configuration.name) inside controller, you'll see activesupport::configurable::configuration in log.