我是一名从事全栈开发的学生。
我正在尝试将我的Django应用程序与sqlite3部署到Heroku。
我正在尝试创建一个超级用户：heroku run python manage.py
它给出错误django.db.utils.Operatorerror：no such table：auth_user
我已经运行了代码heroku run python.manage.py migrate，它都显示OK。
但是当我运行createsuperuser时，它显示了21个未应用的迁移。
我也运行python manage.py migrate，它没有说migrate.You have 21 unapplied migration(s). Your project may not work properly until you apply the migrations for app(s): admin, auth, contenttypes, recipe, sessions, user. Run 'python manage.py migrate' to apply them.
不知道是什么错误以及如何修复它。
当我在settings.py下面的最后3行添加数据库配置时，我的代码显示警告

"""
Django settings for recipe_project project.

Generated by 'django-admin startproject' using Django 4.2.7.

For more information on this file, see
https://docs.djangoproject.com/en/4.2/topics/settings/

For the full list of settings and their values, see
https://docs.djangoproject.com/en/4.2/ref/settings/
"""
import os
from pathlib import Path

# Build paths inside the project like this: BASE_DIR / 'subdir'.
BASE_DIR = Path(__file__).resolve().parent.parent

# Quick-start development settings - unsuitable for production
# See https://docs.djangoproject.com/en/4.2/howto/deployment/checklist/

# SECURITY WARNING: keep the secret key used in production secret!
SECRET_KEY = os.environ.get('DJANGO_SECRET_KEY','django-insecure-ml49cp(e)=yakpevh4xz)3w)6xuq6kv7g&3^xf^)gr-n3&p#%9')

# SECURITY WARNING: don't run with debug turned on in production!
DEBUG = False

ALLOWED_HOSTS = ['127.0.0.1', 'localhost']

# Application definition

INSTALLED_APPS = [
    'django.contrib.admin',
    'django.contrib.auth',
    'django.contrib.contenttypes',
    'django.contrib.sessions',
    'django.contrib.messages',
    'django.contrib.staticfiles',
    # recipe_project-related apps
    'recipe',
    'user',
]

MIDDLEWARE = [
    'django.middleware.security.SecurityMiddleware',
    'whitenoise.middleware.WhiteNoiseMiddleware',
    'django.contrib.sessions.middleware.SessionMiddleware',
    'django.middleware.common.CommonMiddleware',
    'django.middleware.csrf.CsrfViewMiddleware',
    'django.contrib.auth.middleware.AuthenticationMiddleware',
    'django.contrib.messages.middleware.MessageMiddleware',
    'django.middleware.clickjacking.XFrameOptionsMiddleware',
]

ROOT_URLCONF = 'recipe_project.urls'

TEMPLATES = [
    {
        'BACKEND': 'django.template.backends.django.DjangoTemplates',
        'DIRS': [BASE_DIR / 'templates'],
        'APP_DIRS': True,
        'OPTIONS': {
            'context_processors': [
                'django.template.context_processors.debug',
                'django.template.context_processors.request',
                'django.contrib.auth.context_processors.auth',
                'django.contrib.messages.context_processors.messages',
            ],
        },
    },
]

WSGI_APPLICATION = 'recipe_project.wsgi.application'

# Database
# https://docs.djangoproject.com/en/4.2/ref/settings/#databases

DATABASES = {
    'default': {
        'ENGINE': 'django.db.backends.sqlite3',
        'NAME': BASE_DIR / 'db.sqlite3',
    }
}

# Password validation
# https://docs.djangoproject.com/en/4.2/ref/settings/#auth-password-validators

AUTH_PASSWORD_VALIDATORS = [
    {
        'NAME': 'django.contrib.auth.password_validation.UserAttributeSimilarityValidator',
    },
    {
        'NAME': 'django.contrib.auth.password_validation.MinimumLengthValidator',
    },
    {
        'NAME': 'django.contrib.auth.password_validation.CommonPasswordValidator',
    },
    {
        'NAME': 'django.contrib.auth.password_validation.NumericPasswordValidator',
    },
]

# Internationalization
# https://docs.djangoproject.com/en/4.2/topics/i18n/

LANGUAGE_CODE = 'en-us'

TIME_ZONE = 'UTC'

USE_I18N = True

USE_TZ = True

# Static files (CSS, JavaScript, Images)
# https://docs.djangoproject.com/en/3.2/howto/static-files/

STATIC_URL = '/static/'
STATICFILES_DIRS=[

]

# The absolute path to the directory where collectstatic will collect static files for deployment.
MEDIA_ROOT = os.path.join(BASE_DIR, 'media')
STATIC_ROOT = os.path.join(BASE_DIR, 'staticfiles')

MEDIA_URL = '/media/'

# Default primary key field type
# https://docs.djangoproject.com/en/4.2/ref/settings/#default-auto-field

DEFAULT_AUTO_FIELD = 'django.db.models.BigAutoField'

# Heroku: Update database configuration from $DATABASE_URL.
import dj_database_url
db_from_env = dj_database_url.config(conn_max_age=500)
DATABASES['default'].update(db_from_env)

字符串
错误是：
根目录：没有设置DATABASE_URL环境变量，因此没有设置数据库
我已经谷歌试图解决，但无济于事。
请告知