message: Fix async documentation commit to github.
diff: @@ -10,7 +10,9 @@ var github = new Github({
  });
  var repository = github.getRepo('surveyjs', 'service');
  +
  function commit(inputPath, outputPath, comment) {
  + return new Promise(function(resolve, reject) {
  var content = fs.readFileSync(inputPath, 'utf8');
  repository.writeFile(
  'master',
  @@ -24,18 +26,20 @@ function commit(inputPath, outputPath, comment) {
  console.log('Success: ' + log);
  }
  else{
  - console.log('Failure: ' + log);
  + console.log('Failure: ' + log + "\n" + err);
  }
  + resolve();
  }
  );
  + });
  }
  -commit('doc_generator/classes.json', 'surveyjs.io/App_Data/Docs/classes.json', 'Updated Classes API documentation');
  -commit('doc_generator/pmes.json', 'surveyjs.io/App_Data/Docs/pmes.json', 'Updated Properties API documentation');
  -commit('docs/sidebar.json', 'surveyjs.io/App_Data/Docs/sidebar.json', 'Updated SideBar');
  -commit('docs/CreateQuiz.md', 'surveyjs.io/App_Data/Docs/CreateQuiz.md', 'Updated CreadQuiz.md');
  -commit('docs/LibraryOverview.md', 'surveyjs.io/App_Data/Docs/LibraryOverview.md', 'Updated LibraryOverview.md');
  -commit('docs/Question/visibleIf.md', 'surveyjs.io/App_Data/Docs/Question/visibleIf.md', 'Updated visibleIf.md');
  -commit('docs/images/builder-adorners.png', 'surveyjs.io/Content/Images/docs/builder-adorners.png', 'Updated builder-adorners.png');
  -commit('docs/images/builder-question-editor.png', 'surveyjs.io/Content/Images/docs/builder-question-editor.png', 'Updated builder-question-editor.png');
  -commit('docs/images/choicesbyurl.png', 'surveyjs.io/Content/Images/docs/choicesbyurl.png', 'Updated choicesbyurl.png');
  +commit('doc_generator/classes.json', 'surveyjs.io/App_Data/Docs/classes.json', 'Updated Classes API documentation').then(
  + () => commit('doc_generator/pmes.json', 'surveyjs.io/App_Data/Docs/pmes.json', 'Updated Properties API documentation')).then(
  + () => commit('docs/sidebar.json', 'surveyjs.io/App_Data/Docs/sidebar.json', 'Updated SideBar')).then(
  + () => commit('docs/CreateQuiz.md', 'surveyjs.io/App_Data/Docs/CreateQuiz.md', 'Updated CreadQuiz.md')).then(
  + () => commit('docs/LibraryOverview.md', 'surveyjs.io/App_Data/Docs/LibraryOverview.md', 'Updated LibraryOverview.md')).then(
  + () => commit('docs/Question/visibleIf.md', 'surveyjs.io/App_Data/Docs/Question/visibleIf.md', 'Updated visibleIf.md')).then(
  + () => commit('docs/images/builder-adorners.png', 'surveyjs.io/Content/Images/docs/builder-adorners.png', 'Updated builder-adorners.png')).then(
  + () => commit('docs/images/builder-question-editor.png', 'surveyjs.io/Content/Images/docs/builder-question-editor.png', 'Updated builder-question-editor.png')).then(
  + () => commit('docs/images/choicesbyurl.png', 'surveyjs.io/Content/Images/docs/choicesbyurl.png', 'Updated choicesbyurl.png'));
  