Laravel Illuminate Schema : Modify nullable

gistfile1.php

**Migration code**
<?php
Schema::table('users', function(Blueprint $table)
	{
		$table->setNullable('username', true);
	});

**\Illuminate\Database\Schema\Blueprint**
<?php
public function setNullable($column_name, $setNullable=true)
	{
		return $this->addCommand('setNullable', compact('column_name', 'setNullable'));
	}

**\Illuminate\Database\Schema\Grammars\MySqlGrammar.php**
<?php
public function compileSetNullable(Blueprint $blueprint, Fluent $command)
	{
		$column_name = $command->column_name;

		$setNull = $command->setNullable ? 'default null' : 'not null';

		$table = $this->wrapTable($blueprint);

		return "alter table {$table} modify {$column_name} varchar(255) ".$setNull;
	}