add notes for FQL queries in user model
require friends friends info
store friend_uids as json
when user is created, add all friends to user list
add birthday to user
fix birthday parse bug
store both uid and mutual friend count in db
store friends in db sorted by mutual friend count in descending order
efficient sorting and return of friends
add lazy load to friend images
fix N+1 query on friends
add height and width to image for lazy load
modify lazy load to not require initial scroll to load photos
change back lazy load to use scroll instead of load