How do you translate content of module admin controller?

[Jurist]

I've created a module that adds a link to marketplace on product page (for example to amazon or eBay).

It adds a tab to back office, after accessing that tab you see it's AdminController who handles the form and saving the link (url, name, type, related product) to database. It all works well.

However now I need to create a different link for different language.

I've created appropriate _lang database, however despite this, when I try to save new object, it says Property Mwrmarketplacebuttons->mwr_content is empty. That's the field that needs to be translated.

So far I've added:

    public function __construct() 
    {
        $this->bootstrap = true;
        $this->table = 'mwrmarketplacebuttons';
        $this->className = 'Mwrmarketplacebuttons';
        $this->lang = TRUE;
        $this->bootstrap = TRUE;
        $this->addRowAction('edit');
        $this->addRowAction('delete');
        $this->context = Context::getContext();

 

and my input looks like that:

                'input' => array(
                    array(
                        'type' => 'text',
                        'label' => $this->l('Button URL'),
                        'name' => 'mwr_content',
						'id' => 'mwr_content',
						'lang' => true,
                        'size' => 33,
                        'desc' => $this->l('Full listing address. Example: https://amazon.com/your-listing-url'),
                        'required' => true
                    ),

my sql for lang table:

        Db::getInstance()->Execute('
            CREATE TABLE IF NOT EXISTS `'._DB_PREFIX_.'mwrmarketplacebuttons` (
                `id_mwrmarketplacebuttons` int(11) NOT NULL AUTO_INCREMENT,
                `mwr_button_type` int(11) DEFAULT NULL,
                `mwr_content` varchar(5000) DEFAULT NULL,
                `mwr_product` int(11) DEFAULT NULL,
                `mwr_product_name` varchar(5000) DEFAULT NULL,
                `mwr_status` int(11) DEFAULT 0,
                `active` int(11) DEFAULT 0,
                PRIMARY KEY (`id_mwrmarketplacebuttons`)
        ) ENGINE='._MYSQL_ENGINE_.' default CHARSET=utf8');
        Db::getInstance()->Execute('
            CREATE TABLE IF NOT EXISTS `'._DB_PREFIX_.'mwrmarketplacebuttons_lang` (
                `id_mwrmarketplacebuttons` int(10) unsigned NOT NULL,
                `id_lang` int(10) unsigned NOT NULL,
				`mwr_content` TEXT DEFAULT NULL,
                PRIMARY KEY (`id_mwrmarketplacebuttons`,`id_lang`),
            KEY `id_mwrmarketplacebuttons` (`id_mwrmarketplacebuttons`)
        ) ENGINE='._MYSQL_ENGINE_.' default CHARSET=utf8');

anything else I need to change to make it work?

When I add new button it looks good, but it doesn't save it. Picture attached.

Help appreciated.