extract status field to a function, for future refactoring
rename to 'all.ejs', it should be a one-page app..
start using socket.io
add session
now it can pair together via socket.io
add some TODOs for reference
divide into send & receive button; add assert function
also pass fileName and fileSize other than partnerID when paired
it can confirm to send/receive with the hint of fileName & fileSize