Made a couple of tiny styling changes to comment form
Added last_vote and last_comment cached columns to Submission model
Added the ability to edit submissions
Added support for Markdown in comments
Highlight counts for new votes and comments
Added support for themes (why? I don't know)
Added news items to the front page

Also added admin field to User model, so that admins can post
news items
Fixed up little issue with highlighting new items
Updated seeds.rb to populate the DB with news items
Nice little flair: focus on the comment textarea once it appears
Remember the user's theme preference by session
Added admin view of all users
Added default of false back in to User#admin
Updated seeds.rb with random creation times