$scope.create = function(isValid) {
      if (isValid) {
        var article = new Articles({
          title: this.title,
          content: this.content
        });
        article.$save(function(response) {
          $scope.articles.push(response);
        });

        this.title = '';
        this.content = '';
      } else {
        $scope.submitted = true;
      }
    };