public async Task <Classroom> postAsync(ClasroomRequest request)
{
Classroom model = new Classroom();
model.Name = request.Name;
model.Teacher = await _teacher.GetByEmail(request.Teacher);
var newModel = await _repository.PostAsync(model);
return(_repository.Find(x => x.Id == newModel.Id, x => x.assignments, x => x.Posts, x => x.Students, x => x.Teacher));
}