Profile the time spend on fetch stories. Optimize the call from 6000ms to 1300ms.
query user stories :  625 ms
find by user own top_stories!
map ids to BSON objectID :  676 ms
chop first num stories :  676 ms
query top stories :  1361 ms
modify each story :  1370 ms
sort story by score :  1370 ms
Total FindAll time spent :  1377 ms