DynamoDB Client for Rails Application

dynamodb_client.rb

## /config/initializers/dynamodb_client.rb
module DynamodbClient
  def self.initialize!
    client_config = if Rails.env.development?
                      {
                          region: 'us-west-2',
                          endpoint: 'http://localhost:8000'
                      }
                    else
                      {
                          access_key_id: Rails.application.secrets.dynamodb_access_key_id,
                          secret_access_key: Rails.application.secrets.dynamodb_secret_access_key,
                          region: Rails.application.secrets.dynamodb_region
                      }
                    end
    @@client ||= Aws::DynamoDB::Client.new(client_config)
  end

  module_function

  def client
    @@client
  end
end

Im getting the follow error:

irb(main):005:0> DynamodbClient.client
Traceback (most recent call last):
        2: from (irb):5
        1: from config/initializers/dynamodb_client.rb:22:in `client'
NameError (uninitialized class variable @@client in DynamodbClient)

Same here.