anchor.diff:    TextColumn get custom => text().map(const CustomConverter())();
   }
   
  -class PureDefaults extends Table {
  -  IntColumn get id => integer().autoIncrement()();
  +class PureDefaults extends Table with AutoIncrement {
     TextColumn get txt => text().nullable()();
   }
   
  
positive.code: }
  
  @DataClassName('Category')
  class Categories extends Table {
    IntColumn get id => integer().autoIncrement()();
    TextColumn get description =>
        text().named('desc').customConstraint('NOT NULL UNIQUE')();
  }
  
negative.code:   IntColumn get category => integer().nullable()();
  }
  
  class Users extends Table with AutoIncrement {
    TextColumn get name => text().withLength(min: 6, max: 32)();
    BoolColumn get isAwesome => boolean().withDefault(const Constant(true))();
  
  