title: Receiving 'invalid form: crispy' error when trying to use crispy forms filter on a form in Django, but only in one django app and not the other?
body: <p>When trying to use the <code>crispy</code> filter I receive an error:</p>
  
  <blockquote>
    <p>django.template.exceptions.TemplateSyntaxError: Invalid filter:
    'crispy'</p>
  </blockquote>
  
  <p>I believe this is because <code>Django</code> can for some reason not locate the crispy filter, since when I put in the name of a filter that did not exist I received the same error.</p>
  
  <p>I have used <code>{% load crispy_forms_tags %}</code> at the top of the html document and use <code>{{ form|crispy }}</code> to apply the filter. I have also added the 'crispy forms' app to the <code>settings.py</code> file, and installed the <code>django-crispy-forms</code> package with <code>pip</code>, which I can clearly see using <code>pip freeze</code>. </p>
  
  <p>PLEASE NOTE that the crispy forms filter does work in a different django app for my website, even though I don't think I altered anything in that app's directory (but I could be wrong it's been awhile since I worked in that directory). I can't figure out what's different. I read something about filters attaching to the first app directory it can and that's it, but that info was vague, and when I removed the <code>{% load crispy_forms_tags %}</code> line from the template that used it, the crispy filter still wouldn't work in the new app.</p>
  
  <p>This is the template.</p>
  
  <pre><code>{% extends "breed_identifier/base.html" %}
  (% load crispy_forms_tags %)
  {% block content %}
      &lt;div class="content-section"&gt;
          &lt;form method="POST"&gt;
              {% csrf_token %}
              &lt;fieldset class="form-group"&gt;
                  &lt;legend class="border-bottom mb-4"&gt;Join Today&lt;/legend&gt;
                  {{ form|crispy }}
              &lt;/fieldset&gt;
              &lt;div class="form-group"&gt;
                  &lt;button class="btn btn-outline-info" type="submit"&gt;Sign Up&lt;/button&gt;
              &lt;/div&gt;
          &lt;/form&gt;
          &lt;div class="border-top pt-3"&gt;
              &lt;small class="text-muted"&gt;
                  Already Have An Account? &lt;a class="ml-2" href="#"&gt;Sign In&lt;/a&gt;
              &lt;/small&gt;
          &lt;/div&gt;
      &lt;/div&gt;
  {% endblock content %}
  </code></pre>
  
  <p>This is in my settings.py file.</p>
  
  <pre><code>INSTALLED_APPS = [
      'users.apps.UsersConfig',
      'django.contrib.admin',
      'breed_identifier.apps.BreedIdentifierConfig',
      'django.contrib.auth',
      'django.contrib.contenttypes',
      'django.contrib.sessions',
      'django.contrib.messages',
      'django.contrib.staticfiles',
      'crispy_forms',
  ]
  </code></pre>