code: public function up()
      {
          Schema::table('charges', function (Blueprint $table) {
              // Description support
              $table->string('description')->nullable();
  
              // Linking to charge_id
              $table->bigInteger('reference_charge')->nullable();
          });
  
          Schema::table('charges', function (Blueprint $table) {
              // Linking to charge_id, seperate schema block due to contraint issue
              $table->foreign('reference_charge')->references('charge_id')->on('charges')->onDelete('cascade');
          });
      }
docs: Run the migrations.
  
  @return void