add ability to follow people
only show follow button when user can actually follow the person
style follow button
make hover effect more subtile
add followers and followees to profile page
add unfollow button
fix css for safari
add following activity to feed
fix link to followee
create activity when users follow each other
add record activity to feed
don't display activities which are no longer valid
add positive case to Activity#corrupt? test
style activity feed
fix missing kind image for puzzles in activity feed
add timeline background
add CubingSession
add cubing session activity
add missing space
fix position of puzzle image in activity