Spree active menu - ruby-on-rails

Question

What do i want to achieve?
I'm trying to add an active-menu (highlight current page in the menu) to my spree/ruby on rails application.
What have I tried?
After doing some research I've found this question posted very helpful, but as you might have guessed the implementation of the solution I found didn't get me the result I wanted.
The solution I found was adding the following code to the:
The Code
application_helper.rb
module ApplicationHelper
def active_class(link_path)
current_page?(link_path) ? "active" : ""
end
end
routes.rb
root 'spree/home#home'
get '/specs', to: 'spree/home#specs'
get '/about', to: 'spree/home#about'
get '/purchase', to: 'spree/home#purchase'
get '/support', to: 'spree/home#support'
nav.html.erb
<li class="<%= active_class(root_path) %>">
<%= link_to "Home", root_path %>
</li>
<li class="<%= active_class(purchase_path) %>">
<%= link_to "Purchase", purchase_path %>
</li>
<li>
<%= link_to "About", purchase_path %>
</li>
<li class="<%= active_class(specs_path) %>">
<%= link_to "Technical Details", specs_path %>
</li>
<li class="<%= active_class(support_path) %>">
<%= link_to
The Error
But now, no matter what page I go to I get the following error:
NameError in Spree::Home#purchase
Showing /home/ubuntu/workspace/mystore/app/views/spree/shared/_nav_bar.html.erb where line #9 raised:
undefined local variable or method `purchase_path' for #<#<Class:0x007f35a30c6b80>:0x007f35a3642a00>
Extracted source (around line #9):
</li>
<li class="<%= active_class(purchase_path) %>">
<%= link_to "Purchase", purchase_path %>
</li>
I've tried changing several variables, but to no avail
My question is:
How do i create an active menu in Spree (since it's the root of the problem)

Answer 1

See the reference below. I have used activated instead of active. you can style the activated class thereafter
<div class="collapse navbar-collapse" id="bs-example-navbar-collapse-1">
<ul class="nav navbar-nav navbar-right" id="link-section">
<li class="<%= 'activated' if current_page?(root_path) %>">
<a href="/">Home
<span class="sr-only">(current)</span>
</a>
</li>
<li class="<%= 'activated' if current_page?(new_user_registration_path) %>">
<%= link_to("Register", new_user_registration_path) unless user_signed_in? %>
</li>
<li class="<%= 'activated' if current_page?(pricing_path) %>">
<%= link_to("Pricing", pricing_path) %>
</li>
<li class="">
<% if current_user %>
<%= link_to("Store", shop_path(current_user.shop)) if current_user.shop.present? %>
<% end %>
</li>
<li class="<%= 'activated' if current_page?(new_user_session_path) %>">
<%= link_to("Login", new_user_session_path) unless user_signed_in? %>
</li>
<li class="<%= 'activated' if current_page?(dashboard_path) %>">
<%= link_to("Dashboard", dashboard_path) if user_signed_in? %>
</li>
<li>
</li>
</ul>
</div>