Add judge leaderboard
Add a default scope to Rating so that all retrieve ratings are > 0. Improve average* methods so that we can start to use them in the database. Rspec factories are very broken FYI
Rating tells submission to update average score of its submission
Attempt to fix image loading in production
Fix screenshot helper
allow 7z uploads
Merge branch 'develop'
Fix no-rating errors, unscope Rating in the right places to allow access to zero ratings
Correctly define top entries