define private member in model with variable name leaded by _
define course object structure
replace manual data binding with model filter
depend on shortid
uuid field type implemented with shortid
fix: prohibit form submission when error on password confirming
rename account.set to account.update
course data model and operation (untested)
use model.load to filter account.all query result
util.amap: check input more precisely
only show 1 session expiration notification
import ApplicationError in course module
api: /course/* manage course information
sync data model with server implementation