uninitialized constant API::V1::MusicController

Im realy sorry to ask this when there are a lot of similar posts but none seams to work for me.

/app/controllers/api/v1

class Api::V1::MusicsController < ApplicationController
    def index
      articles = Article.order('created_at DESC');
      render json: {status: 'SUCCESS', message:'Loaded articles', data:articles},status: :ok
    end
end

routes.rb

Rails.application.routes.draw do

  namespace 'api' do
    namespace 'v1' do
      resources :music
    end
  end 

end