Add concept of logged in/out. Added sessions controller and routes to manage this feature. Updated UI to display certain things on logged in/out, and locked down routes that shouldn't be available if logged out.
Add edit/view profile pages. Add edit comments functionality. Add require_ownership helper function to only allow owners of comments/posts to edit them. Also lock down the UI to do the same.
Added voting, including the migrations/models/controller adjustments/forms. User must be logged in to vote and can only vote on each thing once.