blue-twilight/app/Configuration.php

<?php

namespace App;

use Illuminate\Database\Eloquent\Model;
use Illuminate\Notifications\Notifiable;

class Configuration extends Model
{
    use Notifiable;

    /**
     * The attributes that are mass assignable.
     *
     * @var array
     */
    protected $fillable = [
        'key', 'value'
    ];

    /**
     * The attributes that should be hidden for arrays.
     *
     * @var array
     */
    protected $hidden = [
    ];

    /**
     * The table associated with the model.
     *
     * @var string
     */
    protected $table = 'configuration';

    public static function installCompleted()
    {
        return (!is_null(Configuration::where('key', 'install_completed')->first()));
    }
}