add highlights and fix cfp in splashpage

app/models/conference.rb

@@ -43,6 +43,10 @@ class Conference < ActiveRecord::Base
     def confirmed
       where(state: :confirmed)
     end
+
+    def highlights
+      where(is_highlight: true)
+    end
   end
   has_many :event_users, through: :events
   has_many :speakers, -> { distinct }, through: :event_users, source: :user do
@@ -559,10 +563,6 @@ class Conference < ActiveRecord::Base
     email_settings.updated_conference_registration_dates_template
   end
 
-  def keynote_speakers
-    User.with_role(:keynote_speaker, self)
-  end
-
   private
 
   after_create do