Posts atom feed

Dynamically generate an atom feed for posts.
Updated Admin navbar.
Updated routes.

Removed un-needed resources from post_comments. Created resources for Admin::Comments
Refactored "admins" namespace to "admin."
Removed unused view.
Comment administration functionality.

Added the ability for an Admin to moderate comments.
Fixed failing spec
Removed un needed feature test
Removed unused actions and helper methods.
Added  additional test coverage.
Merge branch 'feature/comment-admin' into develop