Add user_id to query_params for the purposes of calculating a hash to avoid cache collisions.

lib/helpers.rb

@@ -74,7 +74,7 @@ helpers do
   def handle_threads_query(comment_threads)
 
     if CommentService.config[:cache_enabled]
-      query_params = params.slice(*%w[course_id commentable_id sort_key sort_order page per_page])
+      query_params = params.slice(*%w[course_id commentable_id sort_key sort_order page per_page user_id])
       memcached_key = "threads_query_#{query_params.hash}"
       cached_results = Sinatra::Application.cache.get(memcached_key)
       if cached_results