Improve trending projects finder

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

app/finders/trending_projects_finder.rb

@@ -2,13 +2,21 @@ class TrendingProjectsFinder
   def execute(current_user, start_date = nil)
     start_date ||= Date.today - 1.month
 
-    projects = projects_for(current_user)
-
     # Determine trending projects based on comments count
     # for period of time - ex. month
-    projects.joins(:notes).where('notes.created_at > ?', start_date).
-      select("projects.*, count(notes.id) as ncount").
-      group("projects.id").reorder("ncount DESC")
+    trending_project_ids = Note.
+      select("notes.project_id, count(notes.project_id) as pcount").
+      where('notes.created_at > ?', start_date).
+      group("project_id").
+      reorder("pcount DESC").
+      map(&:project_id)
+
+    sql_order_ids = trending_project_ids.reverse.
+      map { |project_id| "id = #{project_id}" }.join(", ")
+
+    # Get list of projects that user allowed to see
+    projects = projects_for(current_user)
+    projects.where(id: trending_project_ids).reorder(sql_order_ids)
   end
 
   private