关于 artisan migrate 的问题，如何给 tinyInteger 类型加长度限制？

public function tinyInteger($column, $autoIncrement = false, $unsigned = false)
{
    return $this->addColumn('tinyInteger', $column, compact('autoIncrement', 'unsigned'));
}

怎么设置tinyInteger的长度捏？

    Schema::create('backend_user', function (Blueprint $table) {
        $table->increments('id');
        $table->string('nickname');
        $table->string('email')->unique();
        $table-> tinyInteger('type)->unique();
        $table->string('password', 32);
        $table->timestamps();
    });