ユーザー登録機能の実装

Question

djangoのUserCreateFormを用いて「ユーザー登録機能の実装」をしています。
フォームに内容を入力して送信ボタンを押すと以下のエラー（OperationalError at /diary/user_create/）が出てしまうのですが、何が原因でしょうか？

↓＜エラー内容＞

OperationalError at /diary/user_create/
no such table: diary_user
Request Method:	POST
Request URL:	http://127.0.0.1:8080/diary/user_create/
Django Version:	2.2.3
Exception Type:	OperationalError
Exception Value:	
no such table: diary_user
Exception Location:	C:\Users***\AppData\Local\Programs\Python\Python36\lib\site-packages\django\db\backends\sqlite3\base.py in execute, line 383
Python Executable:	C:\Users***\AppData\Local\Programs\Python\Python36\python.exe
Python Version:	3.6.3
Python Path:	
['C:\Users\***\Udemy\django\project(instagram)',
 'C:\Users\***\AppData\Local\Programs\Python\Python36\python36.zip',
 'C:\Users\***\AppData\Local\Programs\Python\Python36\DLLs',
 'C:\Users\***\AppData\Local\Programs\Python\Python36\lib',
 'C:\Users\***\AppData\Local\Programs\Python\Python36',
 'C:\Users\***\AppData\Roaming\Python\Python36\site-packages',
 'C:\Users\***\AppData\Local\Programs\Python\Python36\lib\site-packages']

↓<models.py>

from django.db import models
from django.core.mail import send_mail
from django.contrib.auth.models import PermissionsMixin
from django.contrib.auth.base_user import AbstractBaseUser
from django.utils.translation import ugettext_lazy as _
from django.utils import timezone
from django.contrib.auth.base_user import BaseUserManager

class Day(models.Model):
    title = models.CharField('タイトル', max_length = 200)
    text = models.TextField('本文')
    date = models.DateTimeField('日付', default = timezone.now)

    def __str__(self):
        return self.title

class User(AbstractBaseUser):
    email = models.EmailField(_('email address'), unique=True)
    first_name = models.CharField(_('first name'), max_length=30, blank=True)
    last_name = models.CharField(_('last name'), max_length=150, blank=True)

    EMAIL_FIELD = 'email'
    USERNAME_FIELD = 'email'
    REQUIRED_FIELDS = []

    class Meta:
        verbose_name = _('user')
        verbose_name_plural = _('users')

↓<user_create.html>

{% extends "diary/base.html" %}
{% block content %}
<form action="" method="POST">
  {{ form.non_field_errors }}
  {% for field in form %}
  <div class = 'form-group'>
    <label for="{{ field.id_for_label }}">{{ field.label_tag }}</label>
    {{ field }}\
    {{ field.errors }}
  </div>
  {% endfor %}
  {% csrf_token %}
  <button type="submit" class="btn btn-primary btn-lg">送信</button>
</form>

{% endblock %}

↓<forms.py>

from django import forms
from .models import Day, User
from django.contrib.auth.forms import (
    UserCreationForm,
)

class DayCreateForm(forms.ModelForm):
    class Meta:
        model = Day
        fields = '__all__' # ('title', 'text', 'date')

class UserCreateForm(UserCreationForm):
    class Meta:
        model = User
        fields = ('email',)

↓<views.py>

from django.conf import settings
from django.contrib.auth import get_user_model
from django.contrib.auth.mixins import LoginRequiredMixin
from django.contrib.auth.views import (LoginView, LogoutView)
from django.contrib.sites.shortcuts import get_current_site
from django.shortcuts import render, redirect, get_object_or_404
from django.http import Http404, HttpResponseBadRequest
from django.urls import reverse_lazy
from django.views import generic
from .forms import (DayCreateForm, UserCreateForm)
from .models import Day

# ユーザ関連
from django.contrib.auth import login
from django.contrib.auth.forms import UserCreationForm
from django.http import HttpResponseRedirect
from django.views.generic.edit import CreateView

class IndexView(generic.ListView):
    model = Day
    paginate_by = 3

class AddView(LoginRequiredMixin, generic.CreateView):
    model = Day
    form_class = DayCreateForm
    success_url = reverse_lazy('diary:index')

class UpdateView(LoginRequiredMixin, generic.UpdateView):
    model = Day
    form_class = DayCreateForm
    success_url = reverse_lazy('diary:index')

class DeleteView(LoginRequiredMixin, generic.DeleteView):
    model = Day
    success_url = reverse_lazy('diary:index')

class DetailView(generic.DetailView):
    model = Day


class UserCreate(generic.CreateView):
    template_name = 'diary/user_create.html'
    form_class = UserCreateForm

    def form_valid(self, form):
        user = form.save(commit = False)
        user.save()
        return redirect('diary:user_create_done')


class UserCreateDone(generic.TemplateView):
    template_name = 'register:user_create_done'

Answer 1

no such table: diary_userと出ているのでmigrateが出来ていない可能性があります。
新しいモデルならば

$ python manage.py makemigrations
$ python manage.py migrate

をしてみてください。