Merge pull request #14 from drn/master

Install ActiveAdmin.
Patch ActiveAdmin css precompilation issue.
Customize ActiveAdmin User and Game views.
Customize ActiveAdmin dashboard.
Customize ActiveAdmin views.
Add display_name to Score.
ActiveAdmin fixes.
Fix invalid sorting key on admin Game.
Ignore case when matching Game code.
Fix test suite and add points to admin scores.
Iterate on ActiveAdmin.