public function add(SpecificationContract $specification)
    {
        $this->items->put($specification->uid(), $specification);

        return $this;
    }
public function add(SpecificationContract $specification)
    {
        $this->items->put($specification->uid(), $specification);

        return $this;
    }
public function add ( SpecificationContract $ specification ) { $ this -> items -> put ( $ specification -> uid ( ) , $ specification ) ; return $ this ; }
Add requirement specification.

@param  \Orchestra\Contracts\Installation\Specification  $specification

@return $this
Add requirement specification .