How to use passport strategies

<%= @topic_view.topic.title %>
<%= @topic_view.topic.average_rating %> <%= @topic_view.topic.posts.count { |p| !!p.custom_fields['rating'] } %>

Trying to pass this challenge:
https://learn.freecodecamp.org/information-security-and-quality-assurance/advanced-node-and-express/how-to-use-passport-strategies/

getting the error:

Error: secret option required for sessions

here is the link to my app