post_path has no route on Getting Started With Rails

I’m on Step 5.12 on the Getting Started With Rails tutorial, and I’m getting an error on http://localhost:3000/posts

ActionController::UrlGenerationError in Posts#index
Showing c:/mowes/www/rails_projects/blog/app/views/posts/index.html.erb where line #16 raised:

No route matches {:action=>"show", :controller=>"posts"} missing required keys: [:id]

Extracted source (around line #16):

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<tr>

<td><%= post.title %></td>

<td><%= post.text %></td>

       <td><%= link_to 'Show', **post_path** %></td>

<td><%= link_to 'Edit', edit_post_path(post) %></td>

</tr>

<% end %>

Is there anything that should be defined in routes.rb ?

This seems to be fixed in the latest docs.

at - http://edgeguides.rubyonrails.org/getting_started.html

The highlighted line should be: