adds update listing method to in memory and orm with spec in shared.
beginning of update listing usecase
update listing works. need to add autocreate prototype reservation
Merge branch 'development' of https://github.com/felguerez/aircycle into update_listing
can now update listings. creates a reservation with start date and end date set to nil.

check id params...
request reservation usecase now exists
-> replaces create_reservation usecase with request_reservation usecase.
-> creating or updating a listing no longer generates or affects a "reservation prototype."
-> reservation entity & model now have a status attribute / column
Merge branch 'request_reservation' into development