code: public static void exports(Media groupsConfig, Iterable<TileGroup> groups)
      {
          Check.notNull(groupsConfig);
          Check.notNull(groups);
  
          final Xml nodeGroups = new Xml(NODE_GROUPS);
          nodeGroups.writeString(Constant.XML_HEADER, Constant.ENGINE_WEBSITE);
  
          for (final TileGroup group : groups)
          {
              exportGroup(nodeGroups, group);
          }
  
          nodeGroups.save(groupsConfig);
      }
docs: Export groups to configuration file.
  
  @param groupsConfig The export media (must not be <code>null</code>).
  @param groups The groups to export (must not be <code>null</code>).
  @throws LionEngineException If unable to write to media.