Remove the SuggestionGroup model

app/models/suggestion_group.rb

@@ -1,14 +0,0 @@
-class SuggestionGroup
-  include ActiveModel::Model
-  attr_accessor :speaker, :suggestions
-
-  def self.where(conditions = {})
-    Event.joins(:track).includes(:user).where(conditions).group_by(&:user).map do |speaker, suggestions|
-      SuggestionGroup.new speaker: speaker, suggestions: suggestions
-    end.sort_by { |group| group.speaker.name }
-  end
-
-  def self.for_conference(conference, conditions = {})
-    where conditions.merge({tracks: {conference_id: conference.id}})
-  end
-end