Sample code: "Job board" website models written in Django

job_board_models.py

from django.db import models
from django.urls import reverse
from django.utils import timezone

# Code example for a "job board" style django site 
# Written by Alex Jerez (alexjerez@fastmail.fm)
# for Django 2.0/Python 3.6


JOB_CATEGORIES = (
    # ( slug, verbose)
    ('programming', 'Programming'),
    ('devops-it-sysadmin', 'DevOps & IT'),
    ('business-management', 'Business & Management'),
    ('sales-marketing', 'Sales & Marketing'),
    ('finance-legal', 'Finance & Legal'),
    ('other', 'Other'),
)

JOB_TYPE = (
    ('Full-Time', 'Full-Time'),
    ('Part-Time', 'Part-Time'),
    ('Contract', 'Contract'),
    ('Temporary', 'Temporary'),
    ('Seasonal', 'Seasonal'),
    ('Internship', 'Internship'),
)


class JobPostingManager(models.Manager):
    @staticmethod
    def in_90_days():
        return timezone.datetime.today() + timezone.timedelta(days=90)

    def get_queryset(self):
        return super().get_queryset() \
            .filter(approved=True, visible=True, expires__lte=self.in_90_days())


class JobPosting(models.Model):
    title = models.CharField(max_length=255)
    job_id = models.CharField(max_length=12, unique=True, blank=True, null=True)
    job_type = models.CharField(max_length=20, choices=JOB_TYPE, default="Full Time")
    date_submitted = models.DateField(auto_now_add=True)
    company = models.CharField(max_length=255)
    company_url = models.URLField(blank=True, null=True)
    contact_name = models.CharField(max_length=255)
    contact_email = models.EmailField()
    description = models.TextField(max_length=2000)
    category = models.CharField(max_length=255, choices=JOB_CATEGORIES, default='programming')
    salary_range = models.CharField(max_length=255, blank=True, null=True)
    remote = models.BooleanField(default=False)
    location = models.CharField(max_length=512)
    approved = models.BooleanField(default=False)
    expires = models.DateField(default=JobPostingManager.in_90_days)
    visible = models.BooleanField(default=False)

    # Managers
    objects = models.Manager()
    valid_objects = JobPostingManager()

    @property
    def has_expired(self):
        return timezone.datetime.today().date() > self.expires

    def __str__(self):
        if self.hide_company_name:
            return '%s - %s' % (self.title, self.location)
        return '%s - %s (%s)' % (self.title, self.location, self.company)

    def get_absolute_url(self):
        return reverse('job_detail', args=[self.job_id])

    class Meta:
        ordering = ['-date_submitted', 'category']