firefly-iii/app/models/Budget.php

<?php

use Illuminate\Database\Eloquent\SoftDeletingTrait;
use \Illuminate\Database\Eloquent\Model as Eloquent;
use \Watson\Validating\ValidatingTrait;
/**
 * Class Budget
 */
class Budget extends Eloquent
{
    use SoftDeletingTrait, ValidatingTrait;
    protected     $fillable      = ['name', 'user_id'];
    protected $rules = [
        'user_id' => 'exists:users,id|required',
        'name'    => 'required|between:1,100|alphabasic',
    ];

    /**
     * @return \Illuminate\Database\Eloquent\Relations\HasManyThrough
     */
    public function limitrepetitions()
    {
        return $this->hasManyThrough('LimitRepetition', 'BudgetLimit', 'budget_id');
    }

    /**
     * @return \Illuminate\Database\Eloquent\Relations\HasMany
     */
    public function budgetlimits()
    {
        return $this->hasMany('BudgetLimit', 'budget_id');
    }

    /**
     * @return \Illuminate\Database\Eloquent\Relations\BelongsToMany
     */
    public function transactionjournals()
    {
        return $this->belongsToMany('TransactionJournal', 'budget_transaction_journal', 'budget_id');
    }

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

}