code: public AbstractColumnFamilyTemplate<K,N> addColumn(N columnName, Serializer<?> valueSerializer) {
      columnValueSerializers.put(columnName, valueSerializer);
      activeSlicePredicate.addColumnName(columnName);
      return this;
    }
docs: Add a column to the static set of columns which will be used in constructing
  the single-argument form of slicing operations
  @param columnName
  @param valueSerializer