Moved some behaviour to one place

app/models/event.rb

@@ -70,6 +70,12 @@ class Event < ActiveRecord::Base
         author_id: user.id
       )
     end
+
+    def reset_event_cache_for(target)
+      Event.where(target_id: target.id, target_type: target.class.to_s).
+        order('id DESC').limit(100).
+        update_all(updated_at: Time.now)
+    end
   end
 
   def proper?

app/models/issue.rb

@@ -67,8 +67,6 @@ class Issue < ActiveRecord::Base
   # Thus it will automatically generate a new fragment
   # when the event is updated because the key changes.
   def reset_events_cache
-    Event.where(target_id: self.id, target_type: 'Issue').
-      order('id DESC').limit(100).
-      update_all(updated_at: Time.now)
+    Event.reset_event_cache_for(self)
   end
 end

app/models/merge_request.rb

@@ -287,9 +287,7 @@ class MergeRequest < ActiveRecord::Base
   # Thus it will automatically generate a new fragment
   # when the event is updated because the key changes.
   def reset_events_cache
-    Event.where(target_id: self.id, target_type: 'MergeRequest').
-        order('id DESC').limit(100).
-        update_all(updated_at: Time.now)
+    Event.reset_event_cache_for(self)
   end
 
   def merge_commit_message

app/models/note.rb

@@ -327,9 +327,7 @@ class Note < ActiveRecord::Base
   # Thus it will automatically generate a new fragment
   # when the event is updated because the key changes.
   def reset_events_cache
-    Event.where(target_id: self.id, target_type: 'Note').
-      order('id DESC').limit(100).
-      update_all(updated_at: Time.now)
+    Event.reset_event_cache_for(self)
   end
 
   def set_references