could you please help me join the stock inventory resource to my grid.php? I would like to edit my grid in order to filter by availability "is in stock".
Tried adding this code, but without joining the resource it will not work.
$this->addColumn('inventory_stock_availability ', array( 'header' => Mage::helper('catalog')->__('Status'), 'width' => '100px', 'index' => 'inventory_stock_availability', 'type' => 'options', 'options' => Mage::getSingleton('catalog/inventory_stock_availability ')->getOptionArray(), ));
my grid file is just like this one https://github.com/jayelkaake/enhancedgrid/blob/master/app/code/community/TBT/Enhancedgrid/Block/Catalog/Product/Grid.php