add tracking code for the port number
Merge pull request #31 from twers/51_make_the_session_expire_time_longer

set the session expire time as 30 minutes
Merge branch 'master' of github.com:twers/re-education into 8_add_Google_Analytics
Merge pull request #32 from twers/8_add_Google_Analytics

add tracking code for the port number
make the container of the scratch player overflow hidden
modify text in homepage
modify the text and style in about us
fix build
Merge pull request #34 from twers/56_modify_text

56 modify text
make the exire time as 24 hours