Update index.html.erb

app/views/customers/index.html.erb

@@ -4,7 +4,7 @@
 <%= text_field_tag :search, params[:search], placeholder: "Search Customers" %>
 <%= submit_tag "Search" %>
 <% end %>
-<%= button_to("New Customer", new_customer_path, method: :get) if allowed_to?(:add_customers)%> 
+<%= button_to("New Customer", new_customer_path, method: :get) if User.current.allowed_to?(:add_customers)%> 
 <br/>
 <% if @customers.present? %>
   <br/>