link uploaded ppt images to lapp page
lecture creation bug fix ("throw" when error occurs)
add ppt pages variable
ppt-page bug fix
ppt-page link in lapp.controller
ppt page change bug fix
routes/index.js: update ppt_page bug exists.
ppt-page update bug fix
ppt-page bug fix
ppt-page bug fix (db sync)
ppt-page bug fix: init trace
ppt-page index fix (start from 0)
ppt-page index fix 2
ppt page bug fix