Server Side Validation With Angular Js & Rails

This is a step by step guide for Server Side form validations with AngularJS and Rails backend
Most of the information comes from the following article but I add some important information that was left out:
<a href="http://codetunes.com/2013/server-form-validation-with-angular/">Server Form Validation with Angular.js</a>
We will start with the form:

angular.module('yourApp').controller('PostCtrl', function($scope, PostService) {
  $scope.addPost = function() {<br />    var error, success, newPost;
    newPost = $scope.newPost;
    $scope.errors = {}; //clean up previous server errors

    success = function(result) {
      //things to do if it returns success, here is my example code, will likely be different for you
      $scope.posts.unshift(result);
      $scope.newPost = {};
    };

    error = function(result) {
      angular.forEach(result.data.errors, function(errors, field) {
        $scope.yourForm[field].$setValidity('server', false);
        $scope.errors[field] = errors.join(', ');
      });
    };

    // if you are using $http in your server do this
    // return PostService.create(post).then(success, error);

    // otherwise if you are using $resource in your service do this
    // return PostService.save(post).$promise.then(success, error);
  };
});

Lastly we will change your models Rails Controller so that it returns the errors as json:

if @phrase.save
  render json: @phrase, status: 200
else
  render json: {errors: @phrase.errors}, status: 422
end

You now have server side validation! Congrats!