initial setup fixes, getting ember data running

Your main issue here was that products_controller.rb had no code in the index action, meaning that Ember-data couldn't ask for any data from the server and crapped out.

Second, the product_serializer.rb was only serializing :id, so it wasn't offering any usable data for products.

The last big change is that in Rails, you would never create a column with `camelCase` style, it needs to be `snake_case`. Ember's ActiveModelAdapter you're using in store.js automatically converts those to camelCase style to use in javascript.

So in Ruby, a product is on_sale, but in Ember, a product is onSale. You'll need to `rake db:migrate` to get that change.

I'm going to file some issues for other stuff I see here but this should get you on your feet with Ember Data.