redirect_if_already_contributed.liquid

{% if current_user %}
  {% assign contributed = campaign.contributions | where: user_id: current_user.id | first %}
  {% if contributed %}
    Already contributed!
    <script>
      // Redirect back
      window.location = '{{ request.referer }}'
    </script>
  {% else %}
    Not contributed.
  {% endif %}
{% endif %}