def prepare_custom_fields(options)
      customs = self.class.activity_custom_fields_global.clone
      customs.merge!(self.activity_custom_fields) if self.activity_custom_fields
      customs.merge!(options)
      customs.each do  |k, v|
        customs[k] = PublicActivity.resolve_value(self, v)
      end
    end
def prepare_custom_fields(options)
      customs = self.class.activity_custom_fields_global.clone
      customs.merge!(self.activity_custom_fields) if self.activity_custom_fields
      customs.merge!(options)
      customs.each do  |k, v|
        customs[k] = PublicActivity.resolve_value(self, v)
      end
    end
Prepares and resolves custom fields
 users can pass to `tracked` method
 @private