community-manage/database/migrations/2019_07_22_102837_update_topic_base_count.php

<?php

use Illuminate\Support\Facades\Schema;
use Illuminate\Database\Schema\Blueprint;
use Illuminate\Database\Migrations\Migration;

class UpdateTopicBaseCount extends Migration
{
    /**
     * Run the migrations.
     *
     * @return void
     */
    public function up()
    {
         Schema::table('topic', function (Blueprint $table) {
            $table->integer('base_count')->default(0)->comment('关注虚拟数');
        });
    }

    /**
     * Reverse the migrations.
     *
     * @return void
     */
    public function down()
    {
        //
    }
}