Python Django - Internal Error ProgrammingError relation does not exist

This might probably be a duplicated question, but I can't find a post to answer my questions yet. Any post that is similar to this may help is appreciated.

I tried to host my Django app using heroku.com

git add .
git commit -m "(commit_name)"
git push heroku master

When I tried to test the website (/questions/1), the website shows an Error 500 (Internal Error). First it shows a ProgrammingError: relation does not exist. After that I did $ heroku run python manage.py migrate try to solve the problem. The original error disappeared, but instead this happened:

2020-08-29T11:05:42.668070+00:00 app[web.1]: Internal Server Error: /questions/1
2020-08-29T11:05:42.668070+00:00 app[web.1]:
2020-08-29T11:05:42.668070+00:00 app[web.1]: DoesNotExist at /questions/1
2020-08-29T11:05:42.668071+00:00 app[web.1]: Question matching query does not exist.

Settings.py:

import django_heroku

from pathlib import Path

import os

#--------------------(ommited)--------------------#

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

ALLOWED_HOSTS = ['*']


# Application definition

INSTALLED_APPS = [
    'django.contrib.admin',
    'django.contrib.auth',
    'django.contrib.contenttypes',
    'django.contrib.sessions',
    'django.contrib.messages',
    'django.contrib.staticfiles',
    'myapp',
]

MIDDLEWARE = [
    'django.middleware.security.SecurityMiddleware',
    '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 = 'myweb.urls'

TEMPLATES = [
    {
        'BACKEND': 'django.template.backends.django.DjangoTemplates',
        'DIRS': [os.path.join(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 = 'myweb.wsgi.application'


# Database
# https://docs.djangoproject.com/en/3.1/ref/settings/#databases

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


# Password validation
# https://docs.djangoproject.com/en/3.1/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/3.1/topics/i18n/

LANGUAGE_CODE = 'zh-Hant'

TIME_ZONE = 'Asia/Taipei'

USE_I18N = True

USE_L10N = True

USE_TZ = True


# Static files (CSS, JavaScript, Images)
# https://docs.djangoproject.com/en/3.1/howto/static-files/

STATIC_URL = '/static/'
STATICFILES_DIRS = [
    os.path.join(BASE_DIR, 'static'),
]

STATICFILES_STORAGE = 'whitenoise.storage.CompressedManifestStaticFilesStorage'

STATIC_ROOT = os.path.join(BASE_DIR, 'static')

# Activate Django-Heroku.
django_heroku.settings(locals())

Models.py:

from django.db import models
from django.utils import timezone
import json

# Create your models here.

class Code(models.Model):
    code = models.TextField()
    number = models.IntegerField()

class Question(models.Model):
    title = models.TextField()
    text = models.TextField()
    judges = models.TextField()
    number = models.IntegerField()

    class Meta:
        ordering = ['number']

    def set_judges(self, x):
        self.judges = json.dumps(x)

    def get_judges(self):
        return json.loads(self.judges)

wsgi.py:

import os

from dj_static import Cling
from django.core.wsgi import get_wsgi_application

os.environ.setdefault('DJANGO_SETTINGS_MODULE', 'myweb.settings')

application = Cling(get_wsgi_application())

Any suggestions or things I should try? Thank you.

[EDIT]: It seems that the database is empty now so it cause the error. But when I run the same file in my computer as I git push to heroku, the database isn't empty and it works fine.