code: public ExtendedRelation addRelationship(String baseTableName,
  			UserTable<? extends UserColumn> relatedTable, String relationName,
  			String mappingTableName) {
  
  		UserMappingTable userMappingTable = UserMappingTable
  				.create(mappingTableName);
  
  		return addRelationship(baseTableName, relatedTable, relationName,
  				userMappingTable);
  	}
docs: Adds a relationship between the base and user related table. Creates a
  default user mapping table and the related table if needed.
  
  @param baseTableName
  base table name
  @param relatedTable
  user related table
  @param relationName
  relation name
  @param mappingTableName
  user mapping table name
  @return The relationship that was added
  @since 3.2.0