Make Teacher a full model

[sean-dickinson]

What

• Update the teacher concept to be a full model with CRUD.

Context

• When putting together the quick demo, we made teacher just a string field on classroom rather than a true relation. We now want to go back and make it a full relation with appropriate CRUD
• Teachers have many classrooms
• Teachers belong to a school

Considerations

• There is significant turnover in some of these schools so we will need to consider the best way to handle replacing teachers when they leave and new ones come in. It may make sense to make this a workflow rather than forcing admin users to create a new teacher, assign them to classrooms, and then delete the old teacher.