yii2-gii: Model Generator does NOT generate relations

This issue has originally been reported by @tsanchev at https://github.com/yiisoft/yii2/issues/12741. Moved here by @cebe.

---

What steps will reproduce the problem?

I have used this migration to generate the table

public function up()
{
    if ($this->db->schema->getTableSchema('products', true) !== null) {
        $this->dropTable('products');
    }

    $this->createTable('products', [
        'product_id' => $this->bigPrimaryKey()->unsigned(),

        'category_id' => $this->bigInteger()->unsigned()->notNull(),
        'brand_id' => $this->bigInteger()->unsigned()->notNull(),

        'position' => $this->bigInteger()->unsigned(),

        'product_en' => $this->string()->notNull(),
        'product_bg' => $this->string()->notNull(),
        'product_de' => $this->string()->notNull(),
        'product_ru' => $this->string()->notNull(),

        'description_en' => $this->text(),
        'description_bg' => $this->text(),
        'description_de' => $this->text(),
        'description_ru' => $this->text(),

        'image' => 'LONGBLOB',
        'thumbnail' => 'MEDIUMBLOB',


    ]);

    $this->createIndex('idx-products-category_id', 'products', 'category_id');
    $this->createIndex('idx-products-brand_id', 'products', 'brand_id');

    $this->addForeignKey('fk-products-category_id', 'products', 'category_id', 'categories', 'category_id', 'CASCADE');
    $this->addForeignKey('fk-products-brand_id', 'products', 'brand_id', 'brands', 'brand_id', 'CASCADE');

}

and when I use Model Generator and check “[v] Generate Relations from Current Schema” there is no ActiveQuery methods generated

In the relational tables the primary key is generated using $this->bigInteger()->unsigned()

What is the expected result?

In the model class I expect to have this methods generated

 /**
 * @return \yii\db\ActiveQuery
 */
public function getCategory()
{
    return $this->hasOne(Categories::className(), ['category_id' => 'category_id']);
}

/**
 * @return \yii\db\ActiveQuery
 */
public function getBrand()
{
    return $this->hasOne(Brands::className(), ['brand_id' => 'brand_id']);
}

What do you get instead?

nothing (except rules and attribute labels)

Additional info

Q	A
Yii version	2.0.10-dev
PHP version	5.6.9