FIX: Include 5 participants in topic summary

app/models/topic_participants_summary.rb

@@ -3,6 +3,7 @@
 # This is used on a topic page
 class TopicParticipantsSummary
   attr_reader :topic, :options
+  PARTICIPANT_COUNT = 5 # should match maxUserCount in topic list
 
   def initialize(topic, options = {})
     @topic = topic
@@ -26,7 +27,7 @@ class TopicParticipantsSummary
   end
 
   def top_participants
-    user_ids.map { |id| avatar_lookup[id] }.compact.uniq.take(4)
+    user_ids.map { |id| avatar_lookup[id] }.compact.uniq.take(PARTICIPANT_COUNT)
   end
 
   def user_ids

spec/models/topic_participants_summary_spec.rb

@@ -21,9 +21,9 @@ describe TopicParticipantsSummary do
     fab!(:user4) { Fabricate(:user) }
     fab!(:user5) { Fabricate(:user) }
 
-    it "must never contains the user and at most 4 participants" do
+    it "must never contains the user and at most 5 participants" do
       topic.allowed_user_ids = [user1.id, user2.id, user3.id, user4.id, user5.id]
-      expect(summary.map(&:user)).to eq([user1, user2, user3, user4])
+      expect(summary.map(&:user)).to eq([user1, user2, user3, user4, user5])
     end
 
   end