Drop Down Menu in Django displaying as text field - django

Question

I've followed the process laid out on the Django ModelForm's documentation, as well as a couple of tutorials. My field displays as a standard text-entry, rather than a drop down. Can anyone point me in the right direction?
forms.py
from .models import Authority # change to rating!!!
from django import forms
class AuthorityForm(forms.ModelForm):
class Meta:
model = Authority
fields = ('authority_name',)
views.py
from django.shortcuts import render
from django.views.generic import CreateView
from .models import Authority
from .forms import AuthorityForm
# Create your views here.
class HomeCreateView(CreateView):
model = Authority
form_class = AuthorityForm
template_name = 'home.html'
success_url = 'home.html'
models.py
from django.db import models
# Create your models here.
class Authority(models.Model):
authority_name = models.CharField(max_length = 100)
authority_url = models.URLField()
def __str__(self):
return self.authority_name
class Rating(models.Model):
authority_name = models.CharField(max_length = 100)
ratings = models.CharField(max_length = 20000)
# Could this be reduced if remove the trailing letters of non-int values?
# Perhaps all values could be one-hot encoded
home.html
<h2>Choose Authority:</h2>
<form method="post" novalidate>
{% csrf_token %}
<table>
{{ form.as_table }}
</table>
<button type="submit">Submit</button>
</form>