code: public function double($precision = null)
      {
          return $this->getDb()->getSchema()->createColumnSchemaBuilder(Schema::TYPE_DOUBLE, $precision);
      }
docs: Creates a double column.
  @param int $precision column value precision. First parameter passed to the column type, e.g. DOUBLE(precision).
  This parameter will be ignored if not supported by the DBMS.
  @return ColumnSchemaBuilder the column instance which can be further customized.
  @since 2.0.6