<html>
  <head>
    <title>Chirp</title>
    <script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.2.0/angular.min.js"></script>
    <script src="chirpApp.js"></script>
    <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.2/css/bootstrap.min.css">
    <link rel="stylesheet" href="style.css">
  </head>
  <body ng-app="chirpApp">
    <div id='main' class="container" ng-controller="mainController">
      <div class="col-md-offset-2 col-md-8">
        <div class="clearfix">
          <form ng-Submit="post()">
            <input required type="text" class="form-control" placeholder="Your name" ng-model="newPost.created_by" /> 
            <textarea required class="form-control" maxlength="200" rows="3" placeholder="Say something" ng-model="newPost.text"></textarea>
            <input class="btn submit-btn pull-right" type="submit" value="Chirp!" />
          </form>
          <div id="post-stream">
            <h4>Chirp Feed</h4>
                <div class="post" ng-repeat="post in posts | orderBy:'created_at':true" ng-class-odd="'odd'" ng-class-even="'even'"> 
                  <p>{{post.text}}</p>
                <small>Posted by @{{post.created_by}}</small>
                <small class="pull-right">{{post.created_at | date:"h:mma 'on' MMM d, y"}}</small>
                </div>
          </div>
        </div>
      </div>
    </div>
  </body>
</html>
//chirpApp.js
var app = angular.module('chirpApp', []);

app.controller('authController', function($scope){
  $scope.user = {username: '', password: ''};
  $scope.error_message = '';

  $scope.login = function(){
    //placeholder until authentication is implemented
    $scope.error_message = 'login request for ' + $scope.user.username;
  };

  $scope.register = function(){
    //placeholder until authentication is implemented
    $scope.error_message = 'registeration request for ' + $scope.user.username;
  };
});

app.controller('mainController', function($scope){
  $scope.posts = [];
  $scope.newPost = {created_by: '', text: '', created_at: ''};

  $scope.post = function(){
    $scope.newPost.created_at = Date.now();
    $scope.posts.push($scope.newPost);
    $scope.newPost = {created_by: '', text: '', created_at: ''};
  };
});
/* Styles go here */

1) Change the html file which you want to run to index.html
2) Add your style to style.css
Currently register.html is active
<!--register.html-->
<html>
  <head>
    <title>Chirp</title>
    <script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.2.0/angular.min.js"></script>
    <script src="chirpApp.js"></script>
    <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.2/css/bootstrap.min.css">
    <link rel="stylesheet" href="style.css">
  </head>
  <body ng-app="chirpApp">
    <div  class="container" ng-controller="authController">
      <form class="form-auth" ng-submit="register()">
        <h2>Register</h2>
        <p class="text-warning">{{error_message}}</p>
        <input type="username" ng-model="user.username" placeholder="Username" class="form-control"><br>
        <input type="password" ng-model="user.password" placeholder="Password" class="form-control"><br>
        <input type="submit" value="Register" class="btn btn-primary" />
      </form>
    </div>
  </body>
</html>