Car: POST
Allows user to add a car.
Request
To add a car to a user, make a POST request to:
/api/car/
Response
Status Code: 201
JSON object with the newly instantiated car object.
body: {
__v: 0,
make: 'Subaru',
model: 'Outback',
color: 'Evergreen',
licensePlate: 'PNW-123',
userID: '599611d7166668c23c245b85',
_id: '599611d7166668c23c245b86'
}