<?php

use Illuminate\Support\Facades\Schema;
use Illuminate\Database\Schema\Blueprint;
use Illuminate\Database\Migrations\Migration;

class ChangeValueColumnInSettingsTableToText extends Migration
{

    /**
     * Run the migrations.
     *
     * @return void
     */
    public function up()
    {
        Schema::table('settings', function (Blueprint $table)
        {
            $table->text('value')->nullable()->change();
        });
    }

    /**
     * Reverse the migrations.
     *
     * @return void
     */
    public function down()
    {
        Schema::table('settings', function (Blueprint $table)
        {
            $table->string('value', 255)->nullable()->change();
        });
    }
}

Add migration to change value column to text
Add migration to change value column to text
