code: public ExtendedRelation addMediaRelationship(String baseTableName,
  			MediaTable mediaTable, String mappingTableName) {
  		return addRelationship(baseTableName, mediaTable, mappingTableName);
  	}
docs: Adds a media relationship between the base table and user media related
  table. Creates a default user mapping table and the media table if
  needed.
  
  @param baseTableName
  base table name
  @param mediaTable
  user media table
  @param mappingTableName
  user mapping table name
  @return The relationship that was added