firefly-iii/app/models/AccountMeta.php

<?php
use LaravelBook\Ardent\Ardent as Ardent;

/**
 * AccountMeta
 *
 * @property-read \Account $account
 */
class AccountMeta extends Ardent
{
    /**
     * @var array
     */
    public static $rules
        = [
            'account_id' => 'numeric|required|exists:accounts,id',
            'name'       => 'required|between:1,250',
            'data'       => 'required'
        ];

    /**
     * @var array
     */
    protected $fillable = ['account_id', 'name', 'date'];


    /**
     * @return \Illuminate\Database\Eloquent\Relations\BelongsTo
     */
    public function account()
    {
        return $this->belongsTo('Account');
    }

}