Add users.sign_in_count to GROUP BY clause in #fb_connected_distribution_sql. (How did this even work without it?)

lib/statistics.rb

@@ -79,7 +79,7 @@ SQL
           LEFT OUTER JOIN services on services.user_id = users.id
             AND services.type = 'Services::Facebook'
           #{self.where_clause_sql}
-          GROUP BY users.id
+          GROUP BY users.id, users.sign_in_count
 SQL
   end