dairy-app-api/app/Http/Resources/UserResource.php

<?php

namespace App\Http\Resources;

use Illuminate\Http\Resources\Json\JsonResource;

class UserResource extends JsonResource
{
    /**
     * Transform the resource into an array.
     *
     * @param  \Illuminate\Http\Request  $request
     * @return array
     */
    public function toArray($request)
    {
        return [
            "id" => $this->id,
            "name" => $this->name,
            "login" => $this->login,
            "avatar" => 'http://' . $request->getHost() . '/' . $this->avatar,
            "api_token" => $this->api_token,
            "group" => $this->group,
        ];
    }
}