code: function backup(args, cb) {
      if (!hexo.config.backup) {
          throw new Error("please add backup info into _config.yml, branch & repo ...");
      }
  
      log(hexo.base_dir)
      process.chdir(hexo.base_dir)
  
      var branch = hexo.config.backup.branch;
      var repo = hexo.config.backup.repo;
  
      // 初始化
      if (args.init || args.i) {
          log("要初始化呀呀");
          run("git init .")
          run(util.format("git checkout --orphan %s",branch));
          run(util.format("git remote add backup %s",repo));
          return;
      }
  
      // 常规备份
      log("要backup");
      run("git add --all")
      run(util.format('git commit -a -m "backup at %s"', getnow()))
      run(util.format("git push backup %s",branch))
      cb();
  }
docs: /*
  将remote name 设为 backup
  git checkout --orphan hexo #hexo branch
  git push backup xxx.git