Has Many relation only persist the last record

Hi all, i am having troubles to persist related records on a 1:n relation.

I have a rate plan table, and i want keep the pricing history of each rate plan. So i have the next database schema:

So, i wrote the model classes as below.

RatePlans.php

    public $id;
    public $name;
    public $slug;
    public $price;
    public $active;

    public function initialize()
    {
        $this->hasMany('id', 'PricingHistory', 'rate_plans_id', [
            'alias' => 'pricing_history'
        ]);
    }

    public function get_source()
    {
        return 'rate_plans';
    }

    public function getPricingHistory($parameters = null)
    {
        return $this->getRelated('pricing_history', $parameters);
    }

PricingHistory.php

    public $id;
    public $price;
    public $time;

    public function initialize()
    {
        $this->belongsTo('rate_plans_id', 'RatePlans', 'id');
    }

    public function get_source()
    {
        return 'pricing_history';
    }

Before change the rate plan price, i created a new PricingHistory model and set the relation between models as below:

            $history = new PricingHistory();
            $history->price = $aModel->price;
            $history->time = time();
            // $aModel is an instance of RatePlans model
            $aModel->pricing_history = array($history);
            $aModel->save();

The last code persist only the last price history record, overwriting other records related to current rate plan. So, i have only one history record per rate plan.

What is wrong with the model mapping ? Or the relation insert ?

Thanks.