Eloquent 如何实现 LEFT OUTER JOIN 查询

请问一下如何用Eloquent实现LEFT OUTER JOIN查询：

Sql语句

SELECT A.id,A.name,B.name fatherName,A.add,A.code,A.`level` FROM FatherArticle A LEFT OUTER JOIN FatherArticle B ON A.fatherid=B.id

表结构迁移：

Schema::create('FatherArticle',function (Blueprint $table){
            $table->uuid('id')->primary()->comment('文章分类ID');
            $table->string('code','120')->comment('文章分类标示');
            $table->string('name','225')->comment('文章分类名称');
            $table->integer('level')->default('0')->comment('排序');
            $table->integer('add')->comment('添加时间');
            $table->string('fatherid')->comment('上级ID');\
            $table->string('describe','')->nullable()->comment('分类描述');
        });

请问大家如何实现的，刚用这套框架不久，之前看了“模型关联”不太明白原理，