viral queue flask form in the waitlist

index.html

{% extends "base.html" %}

{% block content %}

<div class="container">
  <div class="row justify-content-center pt-2">
    {% if referring_uuid %}
    <form action="{{ url_for('main.index') + '?user=' + referring_uuid }}" method="post" class="form-inline">
    {% else %}
    <form action="{{ url_for('main.index') }}" method="post" class="form-inline">
    {% endif %}
      {{ form.hidden_tag() }}
      <div class="form-group mx-sm-3 mb-2">
        {{ form.email(class_='input',
                      placeholder='Your best email…',
                      pattern='(^[a-zA-Z0-9_.+-]+@[a-zA-Z0-9-]+\.[a-zA-Z0-9-.]+$)',
                      required='required',
                      oninvalid="this.setCustomValidity('Please enter a valid email address.')",
                      onchange="try{setCustomValidity('')}catch(e){}") }}
      </div>
      {{ form.submit(class_='btn btn-primary mb-2') }}
    </form>
  </div>
</div>
{% endblock %}