speakers_names is made in sentense using join

app/models/event.rb

@@ -204,11 +204,7 @@ class Event < ActiveRecord::Base
   end
 
   def speaker_names
-    result = Set.new
+    speakers.map(&:name).join(', ')
-    speakers.each do |speaker|
-      result.add(speaker.name)
-    end
-    result.to_a.to_sentence
   end
 
   # Returns emails of all the speaker belongs to a particular event