title: SQLite Expecting a string as Index Column when dropping a column
body: <pre><code>&lt;?php
  
  use Illuminate\Database\Schema\Blueprint;
  use Illuminate\Database\Migrations\Migration;
  
  class RemoveConstructionDateToOrdersTable extends Migration
  {
      /**
       * Run the migrations.
       *
       * @return void
       */
      public function up()
      {
          if (Schema::hasColumn('orders', 'construction_date')) {
              Schema::table('orders', function (Blueprint $table) {
                  $table-&gt;dropColumn('construction_date');
              });
          }
      }
  
      /**
       * Reverse the migrations.
       *
       * @return void
       */
      public function down()
      {
          Schema::table('orders', function (Blueprint $table) {
              $table-&gt;date('construction_date');
          });
      }
  }
  </code></pre>
  
  <p>When I am migrating this laravel migration on a sqlite database, I am getting 
  the following error.</p>
  
  <blockquote>
    <p>InvalidArgumentException: Expecting a string as Index Column</p>
  </blockquote>