code: private static List<UserCustomColumn> createColumns() {
  
  		List<UserCustomColumn> columns = new ArrayList<>();
  		columns.addAll(createRequiredColumns());
  
  		int index = columns.size();
  		columns.add(UserCustomColumn.createColumn(index++, COLUMN_NAME,
  				GeoPackageDataType.TEXT, false, null));
  		columns.add(UserCustomColumn.createColumn(index++, COLUMN_DESCRIPTION,
  				GeoPackageDataType.TEXT, false, null));
  		columns.add(UserCustomColumn.createColumn(index++, COLUMN_WIDTH,
  				GeoPackageDataType.REAL, false, null));
  		columns.add(UserCustomColumn.createColumn(index++, COLUMN_HEIGHT,
  				GeoPackageDataType.REAL, false, null));
  		columns.add(UserCustomColumn.createColumn(index++, COLUMN_ANCHOR_U,
  				GeoPackageDataType.REAL, false, null));
  		columns.add(UserCustomColumn.createColumn(index++, COLUMN_ANCHOR_V,
  				GeoPackageDataType.REAL, false, null));
  
  		return columns;
  	}
docs: Create the style columns
  
  @return columns