code: public GitCommitResponse commit(String comment) throws IOException, JavaGitException {
      // first add the file
      add();
  
      // create a list of filenames and add yourself to it
      List<File> list = new ArrayList<File>();
      list.add(relativePath);
  
      GitCommit gitCommit = new GitCommit();
      return gitCommit.commitOnly(workingTree.getPath(), comment, list);
    }
docs: Commits the file system object
  
  @param comment
  Developer's comment
  
  @return response from git commit