code: public function mapModelToLangName($modelName, $langName)
      {
          $modelName = $this->getClassName($modelName);
          $this->modelToLangName[$modelName] = $langName;
      }
docs: Manually map a class to a model name. This is needed if you overwrite
  a class like User to ExtendedUser. So instead of copying your lang entry
  for extended_user you can map App\ExtendedUser to user
  
  @param string $modelName The classname you want to map
  @param string $langName The name of that class inside lang files
  @return void