scopeWithTranslation where concatenation

[maurocordioli]

hi i have noticed that in scopeWithTranslation the second where for the default language is appended to the main query causing the query emitted by eloquent be similar to
*{external_id_field} in (x,y,z....) and locale={currentlocale} or locale={defaultlocale} . *
without parentization the correct query should be some thing like
*{external_id_field} in (x,y,z....) and( locale={current_locale} or locale={default_locale}) . *
using the wrong query in practice does not came with a wrong final result because the master records are filtered, but the performance are very bad ...

you'll find a possible correction of the query scope below

 /**
     * This scope eager loads the translations for the default and the fallback locale only.
     * We can use this as a shortcut to improve performance in our application.
     *
     * @param Builder $query
     */
    public function scopeWithTranslation(Builder $query)
    {
        $query->with(['translations' => function(Relation $q){
            $q->where(function ($query) {
            $query->where($this->getTranslationsTable().'.'.$this->getLocaleKey(), $this->locale());

            if ($this->useFallback()) {
                return $query->orWhere($this->getTranslationsTable().'.'.$this->getLocaleKey(), $this->getFallbackLocale());
            }
            });

        }]);
    }