Fixes #283, 

Add user serializer to not give out user email address over unprotected API show.

#What's new
* Added user serializer to not give out email address over unauthorized API access
* Add show to skip_before_action so that the user is fetched from the API when non-logged in users view a guide.
* Fix markdown directory reference in Angular (I think?)
* Removed references to GUIDE_ID, AUTH_TOKEN, and USER_ID.

What's next?
* Is there a way to specify two different API serializers for the same endpoint? Probably.
* Add rating to guides.