Kills and Neutralizations can only be accessed with email param
Rename Kill.type to Kill.kind
Account for variable rename
Do not let users kill people who are not targets
Add some helpful methods to User

in_game?: synonym for team.in_game?
alive?: returns whether the user is alive or not
dead?: synonym for !alive?
Cannot do this
Fix User.alive?
Do not let users kill dead people
Account for a nil participation_id
Add terminators? method to Team
Better default value to @kind
Add default_participation_id method
Fix target_must_be_on_target_team validation
Better participation_id value