Ember Routing/Lookup with Attributes other than ID - ember.js

Question

I thought I had a fairly simple solution to find models with attributes other than ID, but I'm running into one problem.
Current setup:
Ember Router:
App.Router.map ->
#resource "posts", ->
#route "show", {path: ':slug'}
App.PostsShowRoute = Ember.Route.extend
serialize: (model, params) ->
object = {}
name = params[0]
object[name] = model.get('slug')
return object
model: (params) -> App.Post.find(params.slug)
Rails Controller:
class PostsController < ApplicationController
def show
#post = Post.find_by_slug(params[:id])
render json: #post
end
end
THE PROBLEM
If params.slug == "some-post", when post object is returned from the server, post.id == "some-post". This messes up all the associations.
This is probably because DS.Store is assuming that if I call find(something), something is the id. I would have expected that the response from the server would overwrite this assumption, but it doesn't.
Is there a better way to do this? My use case is extremely simple. All I need to do is serialize and deserialize a post object by the slug attribute.
I'm using Ember Data revision 11

Answer 1

The solution turned out to be findQuery. I was using this some time ago, but I didn't know how to make use of the promise.
model: (params) ->
#get('store').findQuery(App.Post, {slug: params.slug}).then (data) ->
return data.get('firstObject')
and on the rails side:
class PostsController < ApplicationController
def index
#posts = params[:slug] ? Post.where(slug: params[:slug]) : Post.homepage
render json: #posts
end