docs: function checkRequirements () {
        // Check if git version meets requirements
        var gitVersion = (shelljs.exec('git --version', {silent: true}).output.match(/\d+\.\d+\.\d+/) || []).shift();
        if (!gitVersion || semver.lt(gitVersion, '1.8.0')) {
          throw('Current Git version is ' + gitVersion + '. This plugin requires Git >= 1.8.0.');
        }
  
        // Check that build directory exists
        if (!fs.existsSync(options.dir)) {
          throw('Build directory "' + options.dir + '" doesn\'t exist. Nothing to version.');
        }
  
        // Check that build directory conteins files
        if (fs.readdirSync(options.dir).length === 0) {
          throw('Build directory "' + options.dir + '" is empty. Nothing to version.');
        }
  
        // If connectCommits is true check that the main project's working
        // directory is clean
        if (options.connectCommits) {
          var gitDiffOutput = shelljs.exec('git diff').output;
          if (gitDiffOutput !== '') {
            throw ('There are uncommitted changes in your working directory. \n' +
            'Please commit changes to the main project before you commit to \n' +
            'the built code.\n');
          }
        }
  
        if (options.shallowFetch && semver.lt(gitVersion, '1.9.0')) {
          throw('Current Git version is ' + gitVersion + '. Option "shallowFetch" is supported on Git >= 1.9.0.');
        }
      }