community-manage/app/Models/CategoryTopic.php

<?php
/**
 * Created by PhpStorm.
 * User: Administrator
 * Date: 2019/6/6
 * Time: 15:34
 */
namespace App\Models;
use Illuminate\Database\Eloquent\Model;

class CategoryTopic extends Model
{
    //
    protected $table = 'category_topic';
    protected $guarded = [];
    //话题
    public function topic()
    {
        return $this->hasOne('App\Models\Topic', 'id', 'topic_id');
    }
    //分类
    public function category()
    {
        return $this->hasOne('App\Models\Category', 'id', 'category_id');
    }
}