working kill model associations?

two associations with players, since a killer has both a kill and a
target. This is trickier to set up.
not sure. going to save work here and hope that it ends up working out
later.

foreign keys killer_id, target_id, user_id
basic kills functionality

you can now kill users.

This is a giant commit - too lazy to split into finding the core
functionality and minor fixes.

Lots and lots of TODOs - one that comes to mind is adding the kill
validation of not being confirmed

Figure out the rest later

one more TODO: gem 'unicorn'