change to class_name for config, to be clear to use a string
set customer to current_user
get conf. classes from methods
use class_name
refactor serializer, add new field time_slot to distinguish between appointment and time slot
typo fixes
fix create children time_slots
add comments to time slots update children method
user time_slot instead of recurring
make recurring default = 1
only admin can find customers
display search form if user is admin
fix before_action
load and display customer_id for admin when edit appointment