def target_repo(upstream=false)
      # TODO: Manually override this and set arbitrary repositories
      if upstream
        server.repository(source_repo).parent.full_name
      else
        source_repo
      end
    end
def target_repo(upstream=false)
      # TODO: Manually override this and set arbitrary repositories
      if upstream
        server.repository(source_repo).parent.full_name
      else
        source_repo
      end
    end
if to send a pull request to upstream repo, get the parent as target
 @return [String] the name of the target repo