Update griffor.rb

### Moar functions
```ruby
def griffor_scores_to_s(scores)
  scores.map{|person| "#{person[0]} => #{person[1]}" }.join("; ")
end

on :cmd, :griffor_min, /^!griffor\s-min\s/ do |msg,options|
  answer(msg, griffor_scores_to_s(sorted.last(10)))
end
```