Updated SQL Table Definitions

Pretty sure I did this a while ago and lost it in the mad reshuffling of repos...

Signed-off-by: Seth Battis <SethBattis@stmarksschool.org>
Merge branch 'master' of github.com:smtech/canvas-ics-sync

Signed-off-by: Seth Battis <SethBattis@stmarksschool.org>

Conflicts:
	doc/canvas-ics-sync.sql