django forms ForeignKey 'value error must be an instance'

I'm trying to port an application with an existing db. I'm using db_column to have django model Foreign Keys correctly while using the existing database names and columns.

models.py

class foo(models.Model):
  foo_id = models.AutoField(primary_key=True, blank=False, null=False)
  foo_name = models.CharField(max_length=500, blank=True, null=True)
  foo_type_lookup = models.ForeignKey('foo_type_lookup', to_field="foo_type_id", db_column="foo_type", blank=True, null=True)

class foo_type_lookup(models.Model):
  foo_type_id = models.AutoField(primary_key=True, blank=False, null=False)
  foo_type = models.CharField(max_length=500, blank=False, null=False)

The table foo_type_lookup has two rows (ids 0 and 1) for foo_type 'bar' and 'baz'. I'm trying to make a form to add a record in the foo table which will have a foreign key to foo_type_lookup. Foo can either be bar or baz.

views.py

   def add_foo(request):
        action = '#'
        errors = None
        if request.method == 'POST':
            form = FooForm(request.POST)

            if form.is_valid():

                form.save(commit=True)

                return home(request)
            else:
                # The supplied form contained errors - just print them to the terminal.
                errors = form.errors
        else:
            # If the request was not a POST, display the form to enter details.
            form = FooForm()

        # Bad form (or form details), no form supplied...
        # Render the form with error messages (if any).
        return render(request, 'foo/add_foo.html', {'form' : form, 'errors' : errors, 'action' : action})

forms.py

CONTACT_FOO_CHOICES = [[0,'Bar'],[1,'Baz']]

class FooForm(forms.ModelForm):
    foo_type_lookup = forms.ChoiceField(widget=RadioSelect(), choices=CONTACT_FOO_CHOICES)
    foo_name = forms.CharField(label='First Name', max_length=500, required=False)

    class Meta:
        model = foo 

        fields = ('foo_name','foo_type_lookup')

I have to iterate over the form object in my template so I can add a jQuery function when the radio buttons are changed. I find this pretty clunky, but I'm not sure of a more django way to accomplish this:

add_foo.html

<h2>add_foo.html</h2>
<form action="{{action}}" method="post" role="form">
    {% csrf_token %}
    {% for field in form %}
        {% if field.auto_id = 'id_foo_type_lookup' %}
           {% for choice in form.foo_type_lookup.field.choices %}
            <li>
              <label for="id_{{ field.html_name }}_{{ forloop.counter0 }}">
                  <input type="radio"
                    id="id_{{ field.html_name }}_{{ forloop.counter0 }}"
                    value="{{ choice.0 }}"
                    {% if choice.0 == '0' %}
                      checked="true"
                    {% endif %}
                    name="{{ field.html_name }}"
                    onchange="someFunction('id_{{ field.html_name }}_{{ forloop.counter0 }}')"/>
                   {{ choice.1 }}
              </label>
            </li>
            {% endfor %}
        {% else %}
        <div class="formfield_err">{{ field.help_text }}</div>
          <div id="{{ field.auto_id }}_container" >
              <div class="formfield_divlbl">{{ field.label_tag }}
              </div>
              <div class="formfield_divfld">{{ field }}
                  {% if field.field.required %}
                  <span class="required">*</span>
                  {% endif %}
              </div>
              <div id="{{ field.auto_id }}_errors">{{ field.errors }}
              </div>
          </div><div class="clear" style="margin-bottom:12px;"></div>
        {% endif %}
    {% endfor %}

    <input type="submit" value="Submit" />
</form>

I get the error:

Cannot assign "'0'": "foo.foo_type_lookup" must be a "foo_type_lookup" instance.

How do I layout the radio buttons for the type lookup to add onchange javascript and supply my ModelForm with an object of 'foo_type_lookup' so the data will save to the database?