== Table edumaterial_types ==
Purpose: store types of material we have
 * type: encoded type
 * description: textual description of type like slides, HTML lecture, homework, CCTF

== Table edumaterial_shared ==
Purpose: store all shared materials
 * ID: unique ID
 * type: encoded type
 * access: student/teacher
 * title
 * location folder or binary content
 * author contact: uid
 

== Table edumaterial_tags ==
 * material ID from edumaterial_shared
 * tag: enables searching 

== Table class_assignments ==
Purpose: Record what is assigned per class, allow for versioning of materials specific to class
 * ID: unique ID
 * title
 * location folder or binary folder
 * PID of the class that's adopting it (idx?)
 * GID of the group that's assigned to (idx?)
 * state: prepared/assigned/expired
 * due_on: date when it is due
 * after_due: show/hide

== Table student_assignments ==
Purpose: Record what is assigned per student, allow for submissions
 * ID: unique ID
 * assignment_ID: ID from class_assignments
 * uid: uid from users
 * state: submitted/not submitted
 * submission_time: datetime
 * submission: binary record or folder where submitted materials are