refactoring: move read_file feature to super class
add notification_area plugin
update notification refs #508
add resizing feature to notification area refs #508
disable animation when resizing notification area
change default font color in notification area
move image file to plugin's assets directory
add online status plugin
move dom manipulation codes to static css files refs #508
update online status plugin refs #508
imporve user sort method refs #508
add direct message plugin refs #508
improve direct message plugin refs #508
open dm page in new tab
stop adding dm link with themselves
flexible omniauth initializer
create new room for dm if the dm room has been deleted
moderate heartbeat rate and add some ids to dom tree
modify for room list plugin
add jira ticket link plugin