Migrate term modifier sets to sorted sets, counting modifications per user
Merge remote-tracking branch 'upstream/master' into modifier_counts

Conflicts:
	spec/lita/handlers/karma_spec.rb
This spec is failing on Travis, though passing locally.

I think this is the bit of non-deterministic behavior
Update the documentation to reflect the new sorted set for modified:<term>, forcing a bump to 2.2.0

Including instructions on how to change the process for upgrading the existing data.
Merge remote-tracking branch 'upstream/master' into modifier_counts

Conflicts:
	lita-karma.gemspec
  lib/lita/handlers/karma.rb
Merge pull request #8 from erikogan/modifier_counts

Count term modifications by user