Adding to document array in Mongo from Angular Controller

I am having an issue inserting a new JSON object into an array of JSON objects in MongoDB from my Angular Controller.

A simple concept of what I am trying to do is for this schema:

var ThingSchema = new mongoose.Schema({
   id: Number,
   items: [{
      item_id: Number,
      item_name: String,
      item_price: Number
   }]
});

And to add it to my mongodb in a the Mongo console I can use:

db.things.update( 
{ "_id": ObjectId("579b7860b168c80c1fe8a32a")},
{ $push: { 
    "items": {
        "item_id" : 134,
        "item_name" : "sampleItem",
        "item_price" : 234.00
    }}
})

However, I'm not sure how I can translate that over to an http request from AngularJS. I used Yeoman to scaffold my app and am more interested in getting a functional prototype right now. In my Angular Controller, I am using this function

addNewItem(thing, newItem) {
    this.$http.put('/api/things/' + thing._id, { 'items': newItem})
      // on success clear the fields
     .then( response => {
        console.log(response);
        alert(this.newItem);
        thing.items.push(newItem);
        newItem = {};
     });
}

When I call this function I add it to my array that I have instantiated, but I cannot access the actual MongoDB even though a 200 response code is returned.

And in my HTML file I have

<form novalidate class="condition-form">
    <fieldset> 
      <input type="number" ng-model="newItem.item_id" name="" placeholder="Enter item id">
      <input type="text" ng-model="newItem.item_name" name="" placeholder="Enter item name">
      <input type="number" ng-model="newItem.item_price" name="" placeholder="Enter item price">
      <input type="submit" ng-click="$ctrl.addNewItem(thing, newItem)" value="Add">
    </fieldset> 
</form>

I'm really at a loss for how I can translate this mongodb call to my MEAN stack application. If it helps I am using Babel with EMCAScript 6. Any help means a lot!

Thanks