docs: public void addRepository(String url) throws ProjectException {
          List<Repository> repositories = getRepositories();
  
          if ( repositories == null ) {
              repositories = new ArrayList<Repository>();
          }
  
          try {
              Repository repository = RepoBuilder.repositoryFromUrl( url );
              repositories.add( repository );
          } catch (MalformedURLException e) {
              throw new ProjectException( e );
          }
  
          getMavenModel().setRepositories( repositories );
      }