```ruby
module Filepicker
  module Rails
    class Configuration
      attr_writer :api_key
      def api_key
        @api_key or raise "Set config.filepicker_rails.api_key"
      end
    end
  end
end
```

Add secret key as config variable
user
```ruby
module Filepicker
  module Rails
    class Configuration
      attr_writer :api_key, :secret_key
      def api_key
        @api_key or raise "Set config.filepicker_rails.api_key"
      end

      def secret_key
        @secret_key
      end
    end
  end
end
```
assistant