一些优化，新增行政区划

updates/create_china_areas_table.php

@@ -0,0 +1,34 @@
+<?php
+
+use Illuminate\Database\Migrations\Migration;
+use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Support\Facades\Schema;
+
+class CreateChinaArea extends Migration
+{
+    /**
+     * Run the migrations.
+     *
+     * @return void
+     */
+    public function up()
+    {
+        Schema::create('china_areas', function (Blueprint $table) {
+            $table->id('code');
+            $table->string('name')->comment('地区');
+            $table->unsignedTinyInteger('level')->index();
+            $table->unsignedBigInteger('pcode')->index()->comment('上级区划');
+            $table->timestamps();
+        });
+    }
+
+    /**
+     * Reverse the migrations.
+     *
+     * @return void
+     */
+    public function down()
+    {
+        Schema::dropIfExists('china_areas');
+    }
+}