src/Neutrino/Database/Schema/Blueprint.php
public function index($columns, $name = null, $type = __FUNCTION__)
    {
        return $this->addIndex($type, $columns, $name);
    }
public function index($columns, $name = null, $type = __FUNCTION__)
    {
        return $this->addIndex($type, $columns, $name);
    }
Specify an index for the table.

@param  string|array $columns
@param  string|null  $name
@param  string       $type Type of index

@return \Neutrino\Database\Schema\Definition