migration to add availability_id to appointments table
appointment validation presence of availability_id, belongs_to availability
availability #has_many appointments
instructor for rails_admin now shows availabilities, lessons, and students if current user is admin
student model in rails admin now shows appointments and instructors if current user is admin
updates to User association methods, new has_many instructors through appointments
Guest model now shows appointments and lessons
guest rails_admin #edit no longer shows instructor or admin fields
instructor #edit in rails_admin doesn't offer capability to make an instructor an admin unless the current user is an admin
Admin rails_admin config shows same fields as instructor in case admin is also instructor
rails_admin ability spatial differences and export capabilities to instructors
User view now shows appointments, lessons, availabilities, students, and instructors if current user is admin
in rails admin list view show start time first
Availabilty #after_create calls #to_forty_five_minute_appointments
Appointment model shows the availability it belongs to in rails admin, availability shows all of its appointments
seeds file seeds another instructor, a student account, and a guest account
new appointment #unavailable? method, instructor can make an appointment unavailable
add 'Unavailable to enum in appointment statuses
TODO comment about when an appt is cancelled/rescheduled, another one needs to take its place
help tip on appointment status explains what Unavailable means