Database models:

1. User
- user id (PK)
- first name
- last name
- password (hashed)
- classes
- email
- phone #
2. Subject
- subject id (PK)
- user id (FK + PK)
- name
- list of lectures
- status (current or past)
3. Lecture
- lecture id (PK)
- user id (FK + PK)
- subject id (FK + PK)
- date
- any categories its in (e.g. week or unit)
- raw transcript
- recording (?audio files are big and expensive to store... tbd)
- concepts array (will depend on future research and how we process transcript)
- {term, definition, student understanding score}
- **redis cache**
4. Quiz
- quiz id
- lecture id
- list of (question, answer) tuples