How to do it...

1. Define your app settings using the getattr() pattern in models.py if you just have one or two settings, or in the app_settings.py file if the settings are extensive and you want to organize them better:

# myproject/apps/magazine/app_settings.py
from django.conf import settings
from django.utils.translation import gettext_lazy as _

# Example:
SETTING_1 = getattr(settings, "MAGAZINE_SETTING_1", "default value")

MEANING_OF_LIFE = getattr(settings, "MAGAZINE_MEANING_OF_LIFE", 42)

ARTICLE_THEME_CHOICES = getattr(
    settings,
    "MAGAZINE_ARTICLE_THEME_CHOICES",
    [
        ('futurism', _("Futurism")),
        ('nostalgia', _("Nostalgia")),
        ('sustainability', _("Sustainability")),
        ('wonder', _("Wonder")),
    ]
)

2. models.py will contain the NewsArticle model, like this:

# myproject/apps/magazine/models.py
from django.db import models
from django.utils.translation import gettext_lazy as _


class NewsArticle(models.Model):
    created_at = models.DateTimeField(_("Created at"),  
     auto_now_add=True)
    title = models.CharField(_("Title"), max_length=255)
    body = models.TextField(_("Body"))
    theme = models.CharField(_("Theme"), max_length=20)

    class Meta:
        verbose_name = _("News Article")
        verbose_name_plural = _("News Articles")

    def __str__(self):
        return self.title

3. Next, in admin.py, we will import and use the settings from app_settings.py, as follows:

# myproject/apps/magazine/admin.py
from django import forms
from django.contrib import admin

from .models import NewsArticle

from .app_settings import ARTICLE_THEME_CHOICES


class NewsArticleModelForm(forms.ModelForm):
    theme = forms.ChoiceField(
        label=NewsArticle._meta.get_field("theme").verbose_name,
        choices=ARTICLE_THEME_CHOICES,
        required=not NewsArticle._meta.get_field("theme").blank,
    )
    class Meta:
        fields = "__all__"


@admin.register(NewsArticle)
class NewsArticleAdmin(admin.ModelAdmin):
 form = NewsArticleModelForm

4. If you want to overwrite the ARTICLE_THEME_CHOICES settings for a given project, you should add MAGAZINE_ARTICLE_THEME_CHOICES in the project settings:

# myproject/settings/_base.py
from django.utils.translation import gettext_lazy as _
# ...
MAGAZINE_ARTICLE_THEME_CHOICES = [
    ('futurism', _("Futurism")),
    ('nostalgia', _("Nostalgia")),
    ('sustainability', _("Sustainability")),
    ('wonder', _("Wonder")),
    ('positivity', _("Positivity")),
    ('solutions', _("Solutions")),
    ('science', _("Science")),
]