I just started learning Yii2 and I have a problem here. I want to set new rule on name field, which would replace all first letters to the uppercase, but I don't know how to set the rule name and I'm constantly getting error messages of it.

Now my model looks like this, I added regex, which is replacing letters to uppercase, but I've no idea how to write that empty string:

['name', 'required'],
        ['name', 'string', 'max' => 255,
            ' ' => '/(^|\s)[a-z]/g'],

Thank you for any help