Accessing virtual attribute from params - ruby-on-rails

Question

ruby 2.1.5
rails 4.2.1
I am trying to figure out how to access a virtual attribute from params.
In my books_controller.rb, I have:
wrap_parameters :books_list
def product_params
params.require(:product).permit(:author_name, :book_name, :books_list)
end
Obviously, the books_list is the virtual attribute. I will be saving it to the books_list table
In my new.html.erb,I have:
<% #title = "Books" %>
<div class="container">
<div class="row">
<div class="col-xs-12 col-sm-12 col-md-12 col-lg-12">
<%= form_for(#books, html: { class: 'form-horizontal' }) do |f| %>
<%= f.error_notification %>
<div class="form-inputs">
<%= f.form_group :author_name do |f| %>
<%= f.label :author_name, class: 'control-label col-md-2' %>
<div class='col-md-8'>
<%= f.text_field :author_name, class: 'form-control' %>
<%= f.error_messages %>
</div>
<% end %>
<div class="form-inputs">
<%= f.form_group :book_name do |f| %>
<%= f.label :book_name, class: 'control-label col-md-2' %>
<div class='col-md-8'>
<%= f.text_field :book_name, class: 'form-control' %>
<%= f.error_messages %>
</div>
<% end %>
<%= f.form_group :books_list do |f| %>
<%= f.label :books_list, class: 'control-label col-md-2' %>
<div class='col-md-8'>
<%= f.text_area :books_list, class: 'form-control' %>
<%= f.error_messages %>
</div>
<% end %>
</div>
<div class="form-actions col-md-offset-2 col-md-10">
<%= f.submit class: 'btn btn-primary' %>
<%= link_to "Cancel", test_sets_path, class: 'btn' %>
</div>
<% end %>
</div>
</div>
</div>
When I submit the form, here's what I get for params:
Parameters: {
"utf8"=>"✓",
"authenticity_token"=>"5mxkibQHkwRnzVU31A6pe9uezsmaWeYbCUgU+gUZPLmiAZPnN6si+smdEePU0lfGITh7gmmyChf/bOY+YQQcQg==",
"books"=>{"author_name"=>"Some Author", "book_name"=>"Dwan Of The Dead"},
"books_list"=>{"{:class=>\"form-control\"}"=>"book1\r\nbook2"},
"commit"=>"Create Book List"
}
I am having trouble accessing the books_list in params. Any ideas?

Answer 1

If books_list column is not exist in #book, it raises error.
There is no method f.form_group in rails, I think you use gem that defines form_group method.
Maybe "books_list"=>{"{:class=>\"form-control\"}"=>"book1\r\nbook2"} parameter is made by some bootstrap gem. you check check name attribute in html source.