How to setup Discogs for RoR

class DiscogsController < ApplicationController
  before_filter :authenticate_user!
  before_filter :check_admin

  before_filter do
    @discogs = Discogs::Wrapper.new("APP_NAME", access_token: session[:access_token])
  end

  def index
    @items_with_discogs = Item.all # Items should have discogs_release_id 
    
    if params[:preprocess]
      @items_with_discogs.each do |item|
        d = @discogs.get_release(item.discogs_id).images[0].resource_url

        # Use with Paperclip
        item.discogs_thumb = URI.parse(d)
        item.avatar = URI.parse(d)

        #logger.debug "DISCOGS RESULT: #{d.images} \n\n"
        
        item.save
      end
    end
  end

  def authenticate
    app_key     = Settings.discogs.api_key
    app_secret  = Settings.discogs.api_secret
    request_data = @discogs.get_request_token(app_key, app_secret, callback_discogs_url)

    session[:request_token] = request_data[:request_token]
    redirect_to request_data[:authorize_url]
  end

  def callback
    request_token = session[:request_token]
    verifier      = params[:oauth_verifier]
    access_token  = @discogs.authenticate(request_token, verifier)

    session[:request_token] = nil
    session[:access_token]  = access_token

    redirect_to :action => "index"
  end

private
  def discogs_params
    params.require(:discogs).permit(:avatar)
  end
end