nil fields throw error in backend

[dgoldstein1]

request:

curl -XPOST \
 "http://localhost:8443/backend/property" \
 -H "content-type: application/json" \
 -H "Authorization: Bearer eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJleHAiOjE1OTU5NjQzNDMsInVpZCI6Ijg0MmZiYjczLWUzNzctNDkxNC1iZmM3LWI0NDJhM2VlZjViYSIsInJvbGUiOiJuYXZpZ2F0b3IifQ.TCtKenywqBx6E9CbjzJ6Ot69k30Niy431NLRyHDNxik" \
 -d '{"address":"520 East Main Street","allow_criminal_records":true,"application_fee":5000,"background_screening_company":"Cville Background Screening","bathrooms":1,"bedrooms":2,"bus_line":true,"contact_method":["phone"],"credit_screening_company":"Cville Credit Screening","deposit":500,"elevator":false,"floor":3,"has_basement":true,"housing_type":"apartment","is_available":true,"last_month_rent_required":true,"monthly_rent":1000,"potential_month_available":5,"property_name":"Davids Apartment","school_district":"CHS","shared_bathrooms":0,"unit_apt_no":"9","voucher_type_accepted":[],"voucher_type_not_accepted":[],"wheelchair_accessibility":true,"where_listed":["Zillow"],"year_available":2020,"zip_code":"22902"}'

response:

{
  "code": 500,
  "error": "internal error"
}

error:

housinghub-a… │   File "/usr/local/lib/python3.6/site-packages/sqlalchemy/engine/base.py", line 1482, in _handle_dbapi_exception
housinghub-a… │     sqlalchemy_exception, with_traceback=exc_info[2], from_=e
housinghub-a… │   File "/usr/local/lib/python3.6/site-packages/sqlalchemy/util/compat.py", line 178, in raise_
housinghub-a… │     raise exception
housinghub-a… │   File "/usr/local/lib/python3.6/site-packages/sqlalchemy/engine/base.py", line 1248, in _execute_context
housinghub-a… │     cursor, statement, parameters, context
housinghub-a… │   File "/usr/local/lib/python3.6/site-packages/sqlalchemy/engine/default.py", line 588, in do_execute
housinghub-a… │     cursor.execute(statement, parameters)
housinghub-a… │   File "/usr/local/lib/python3.6/site-packages/pgdb.py", line 1052, in execute
housinghub-a… │     return self.executemany(operation, [parameters])
housinghub-a… │   File "/usr/local/lib/python3.6/site-packages/pgdb.py", line 1077, in executemany
housinghub-a… │     rows = self._src.execute(sql)
housinghub-a… │ sqlalchemy.exc.IntegrityError: (pg.IntegrityError) ERROR:  null value in column "listing_date" violates not-null constraint
housinghub-a… │ DETAIL:  Failing row contains (88bf2c76-059d-4b15-b54b-3947d3500307, null, null, {}, {}, 520 East Main Street, 22902, 9, Davids Apartment, t, CHS, t, f, 1000, {phone}, t, null, null, 5, 2, 1, 0, t, 5000,
500, t, t, null, {Zillow}, 3, apartment, 2020, Cville Credit Screening, Cville Background Screening, null).
housinghub-a… │
housinghub-a… │ [SQL: INSERT INTO property (id, landlord_id, navigator_id, voucher_type_accepted, voucher_type_not_accepted, address, zip_code, unit_apt_no, property_name, bus_line, school_district,
wheelchair_accessibility, elevator, monthly_rent, contact_method, is_available, date_first_available, last_contact_date, potential_month_available, bedrooms, bathrooms, shared_bathrooms, has_basement, application_fee,
deposit, last_month_rent_required, allow_criminal_records, listing_date, where_listed, floor, housing_type, year_available, credit_screening_company, background_screening_company, last_contacted_by) VALUES (%(id)s,
%(landlord_id)s, %(navigator_id)s, %(voucher_type_accepted)s, %(voucher_type_not_accepted)s, %(address)s, %(zip_code)s, %(unit_apt_no)s, %(property_name)s, %(bus_line)s, %(school_district)s, %(wheelchair_accessibility)s,
%(elevator)s, %(monthly_rent)s, %(contact_method)s, %(is_available)s, %(date_first_available)s, %(last_contact_date)s, %(potential_month_available)s, %(bedrooms)s, %(bathrooms)s, %(shared_bathrooms)s, %(has_basement)s,
%(application_fee)s, %(deposit)s, %(last_month_rent_required)s, %(allow_criminal_records)s, %(listing_date)s, %(where_listed)s, %(floor)s, %(housing_type)s, %(year_available)s, %(credit_screening_company)s,
%(background_screening_company)s, %(last_contacted_by)s)]
housinghub-a… │ [parameters: {'id': UUID('88bf2c76-059d-4b15-b54b-3947d3500307'), 'landlord_id': None, 'navigator_id': None, 'voucher_type_accepted': [], 'voucher_type_not_accepted': [], 'address': '520 East Main Street',
 'zip_code': '22902', 'unit_apt_no': '9', 'property_name': 'Davids Apartment', 'bus_line': True, 'school_district': 'CHS', 'wheelchair_accessibility': True, 'elevator': False, 'monthly_rent': 1000, 'contact_method':
['phone'], 'is_available': True, 'date_first_available': None, 'last_contact_date': None, 'potential_month_available': 5, 'bedrooms': 2, 'bathrooms': 1, 'shared_bathrooms': 0, 'has_basement': True, 'application_fee':
5000.0, 'deposit': 500.0, 'last_month_rent_required': True, 'allow_criminal_records': True, 'listing_date': None, 'where_listed': ['Zillow'], 'floor': 3, 'housing_type': 'apartment', 'year_available': 2020,
'credit_screening_company': 'Cville Credit Screening', 'background_screening_company': 'Cville Background Screening', 'last_contacted_by': None}]
housinghub-a… │ (Background on this error at: http://sqlalche.me/e/gkpj)
housinghub-a… │
housinghub-a… │ 172.20.0.3 - - [28/Jul/2020 16:36:36] "POST /property HTTP/1.1" 500 -