Add initial documentation for using the Django ORM

docs/en/docs/advanced/django-orm.md

@@ -0,0 +1,99 @@
+# Using the Django ORM with FastAPI
+
+In this guide we'll show you how to use Django's ORM with FastAPI.
+
+This can be extremely useful when migrating from Django to FastAPI, as you can reuse your existing Django models and queries. It's also a great way to take advantage of Django's powerful ORM while using FastAPI's modern features.
+
+This tutorial is based on the Django polls tutorial, but you can apply the same concepts to any Django project.
+
+## Prerequisites
+
+- A Django project like the one created from the [Django polls tutorial](https://docs.djangoproject.com/en/stable/intro/tutorial01/)
+- Basic knowledge of FastAPI
+
+## Step 1: Install FastAPI
+
+First, let's install FastAPI in our Django project:
+
+```bash
+# make sure to run this in your Django virtual environment
+pip install fastapi
+```
+
+## Step 2: Set up a basic FastAPI application
+
+Create a `main.py` file:
+
+```python
+from fastapi import FastAPI
+
+app = FastAPI()
+```
+
+In the next steps we'll import the `Question` model from Django, and create a FastAPI endpoint to list all questions.
+
+## Step 3: Import Django models
+
+In your `main.py` file, let's import the `Question` model:
+
+```python
+from polls.models import Question
+```
+
+Make sure to replace `polls` with the name of your Django app.
+
+## Step 4: Create a FastAPI endpoint
+
+Now let's create a FastAPI endpoint to list all questions:
+
+```python
+@app.get("/questions")
+def get_questions():
+    questions = Question.objects.all()
+
+    return [{"question": question.question_text} for question in questions]
+```
+
+## Step 5: Run the FastAPI application
+
+No we can run the FastAPI application:
+
+```bash
+fastapi dev main.py
+```
+
+If you go to `http://localhost:8000/questions` we should see the list of questions, right? 🤔
+
+Unfortunately, we'll get an error:
+
+```text
+django.core.exceptions.ImproperlyConfigured: Requested setting INSTALLED_APPS, but settings are not configured. You must either define the environment variable DJANGO_SETTINGS_MODULE or call settings.configure() before accessing settings.
+```
+
+This error happens because Django settings are not configured before importing the Django models.
+
+## Step 6: Configure Django settings
+
+To fix this error, we need to configure Django settings before importing the Django models.
+
+In the `main.py` add the following code **before** importing the Django models:
+
+```python
+import os
+import django
+
+os.environ.setdefault("DJANGO_SETTINGS_MODULE", "mysite.settings")
+django.setup()
+```
+
+This will configure Django settings before importing the Django models.
+
+## Step 7: Run the FastAPI application
+
+Now you can run the FastAPI application:
+
+```bash
+fastapi dev main.py
+```
+
+And now if we go to `http://localhost:8000/questions` we should see a list of questions! 🎉

docs/en/mkdocs.yml

@@ -151,6 +151,7 @@ nav:
       - advanced/security/http-basic-auth.md
     - advanced/using-request-directly.md
     - advanced/dataclasses.md
+    - advanced/django-orm.md
     - advanced/middleware.md
     - advanced/sub-applications.md
     - advanced/behind-a-proxy.md