Saving upvote value to database (MEAN stack - reddit clone) - angularjs

Question

I have been working on a reddit clone from the thinkster.io tutorial, and I can not figure out how to save upvote values to the database. Could some one please take a look?
// from angularApp.js
.factory('posts', ['$http', 'auth', function($http, auth){
var o = {
posts: []
};
o.upvote = function(post) {
return $http.put('/posts/' + post._id + '/upvote', {
headers: {Authorization: 'Bearer '+auth.getToken()}
}).success(function(data){
post.votes += 1;
});
};
return o;
}])
.controller('MainCtrl', [
'$scope',
'posts',
'auth',
function($scope, posts, auth){
$scope.posts = posts.posts;
$scope.isLoggedIn = auth.isLoggedIn;
$scope.addPost = function(){
//prevents empty posts
if(($scope.title === '') || ($scope.body === '')) { return; }
//creates post
posts.create({
title: $scope.title,
votes: 0,
createdOn: Date.now(),
link: $scope.link,
body: $scope.body,
});
//returns empty values after post is created
$scope.title = '';
$scope.link = '';
$scope.body = '';
};
$scope.incrementUpvotes = function(post){
posts.upvote(post);
};
}])
//mongoose post schema
var PostSchema = new mongoose.Schema({
title: { type: String, required: '{PATH} is required!'},
body: String,
createdOn: { type: Date, default: Date.now },
votes: {type: Number, default: 0},
comments: [{ type: mongoose.Schema.Types.ObjectId, ref: 'Comment' }],
author: String
});
PostSchema.methods.upvote = function(cb) {
this.votes += 1;
this.save(cb);
};
mongoose.model('Post', PostSchema);
// from index.js
// upvote a post
router.put('/posts/:post/upvote', auth, function(req, res, next) {
req.post.upvote(function(err, comment){
if (err) { return next(err); }
res.json(comment);
});
});
//from index.ejs (html)
<i ng-click="incrementUpvotes(post)" class="ion-chevron-up"></i><br>
{{comment.votes}}<br>

Answer 1

o.upvote = function(post) {
return $http.put('/posts/' + post._id + '/upvote', null, { ...