Batch process to update availability
The user has the ability to specify his or her availability for flights.
There is a field for general availability, which can either be 1 or 0. Note that the way the system is currently set up, the field is called not_available, and 1 means that they are not available, 0 means that they are available.
There are also fields for first and last date. These are start and end dates for periods of non-availability or non-availability. Note that it doesn't make sense to specify a period of availability, since the pilot is assumed to be generally available, so the system assumes that any period specified indicates non-availability.
The batch process runs every day. If today's date falls within a period specified by the user, the availability will be set to 1 for not_available.
If the last_date is prior to today, not_available is set to 0, and the first and last date fields are cleared.