Add clear rating method in https://github.com/wazery/ratyrate

ratyrate.rb

module Ratyrate
     def update_rate_average(stars, dimension=nil)
        if average(dimension).nil?
          RatingCache.create! do |avg|
            avg.cacheable_id = self.id
            avg.cacheable_type = self.class.name
            avg.avg = stars
            avg.qty = 1
            avg.dimension = dimension
          end
        else
          a = average(dimension)
          a.qty = rates(dimension).count
          #If there is no rating for the model then delete the row from average rating. You might want to
          # update overall average also if using multiple dimension
          if a.qty == 0
            a.delete
          else
            a.avg = rates(dimension).average(:stars)
            a.save!(validate: false)
          end
        end
     end

    def clear_rating (user, dimension=nil)
        user_rating = user.ratings_given.where(dimension: dimension, rateable_id: id, rateable_type: self.class.name)
        Rate.delete(user_rating.first.id) unless user_rating.nil?
        update_rate_average(0, dimension)
    end
end