CreateItemTag::up PHP Method

    public function up()
    {
        Schema::create('item_tag', function ($table) {
            $table->integer('item_id')->unsigned();
            $table->foreign('item_id')->references('id')->on('items');
            $table->integer('tag_id')->unsigned();
            $table->foreign('tag_id')->references('id')->on('tags');
        });
    }