In order for Django to keep track of our application and be able to create database tables for its models, we have to activate it. To do this, edit the settings.py file and add blog.apps.BlogConfig to the INSTALLED_APPS setting. It should look like this:

INSTALLED_APPS = [
    'django.contrib.admin',
    'django.contrib.auth',
    'django.contrib.contenttypes',
    'django.contrib.sessions',
    'django.contrib.messages',
    'django.contrib.staticfiles',
    'blog.apps.BlogConfig',
]

The BlogConfig class is your application configuration. Now Django knows that our application is active for this project and will be able to load its models.