Angular + Rails + MongoDB(mongoid) delete function won't work - ruby-on-rails

Question

I have an Angular app with a rails back end and using the mongoid gem as a database. I'm trying to make a delete function, but I can't get it to work.
I get
No route matches [DELETE] "/api/tags"
I can't seem to get the ID. I thought I was doing that in the factory. Otherwise, I don't know how to get it.
My code:
angular:
var myApp = angular.module('tagsapp', ['ngRoute', 'ngResource']);
myApp.factory("Tag", function($resource) {
return $resource("/api/tags/:id", { _id: "#id"},
{
'create': { method: 'POST' },
'index': { method: 'GET', isArray: true },
'show': { method: 'GET', isArray: false },
'update': { method: 'PUT' },
'destroy': { method: 'DELETE' }
}
);
})
// Controllers
myApp.controller("TagListCtrl", ['$scope', '$resource', 'Tag', '$location',
function($scope, $resource, Tag, $location) {
$scope.tags = Tag.query();
$scope.saveNewTag = function() {
Tag.create({ tag: $scope.newTag }, function(response){
$scope.tags.push(response);
$scope.newTag = null;
});
}
$scope.deleteTag = function(tagId) {
Tag.destroy({ _id: tagId }, function(response){
var index = $scope.tags.indexOf(tagId);
$scope.tags.splice(index, 1)
$location.path('/')
})
};
}]);
and my rails controller:
class TagsController < ApplicationController
before_action :set_tag, only: [:show, :edit, :update, :destroy]
respond_to :json
def index
#tags = Tag.all
end
def show
#tag = Tag.find(params[:id])
end
def new
#tag = Tag.new
end
def edit
#tag = Tag.find(params[:id])
end
def create
# #tag = Tag.new(tag_params)
tag = Tag.create!(tag_params)
render json: tag, status: 201
end
def update
tag.update_attributes(tag_params)
render json: tag, status: 201
end
def destroy
#tag.destroy
respond_with #tag
end
private
def set_tag
#tag = Tag.find(params[:id])
end
def tag_params
params.require(:tag).permit(:name, :color, :order)
end
end
and my view:
<div ng-controller="TagListCtrl" ng-style="{color: myColor}">
<table>
Name: <input ng-model="newTag.name"> <br>
Color: <input ng-model="newTag.color"> <br>
Order: <input ng-model="newTag.order"> <br>
<button ng-click="saveNewTag()">Save</button>
</div>
<tr ng-show="tags.length" ng-repeat="tag in tags">
<td>{{tag.name}}</td>
<td>{{tag.color}}</td>
<td>{{tag.order}}</td>
<td>
Remove
</td>
</tr>
</table>
</div>
rails routes:
Rails.application.routes.draw do
scope "api", defaults: {format: :json} do
resources :tags
end
root to: "tags#index", anchor: false
end
I'm suspecting that my routes are off. So far, adding a new tag works in the rails index.html.erb. I didn't put in any templates for angular to route to.