activeadmin.md

@@ -38,9 +38,24 @@ filter :country_in, as: :select, collection: Country::ALL
 
 [Source](https://git.altum.com.br/gocase/gocase-factory/blob/develop/app/ui/go_logistics/order/index.rb)
 
-## References
+### References
 
 [ActiveAdmin Filters with Ransack](https://cavewall.jaguardesignstudio.com/2014/05/01/activeadmin-filters-with-ransack/)
 
+## Add pagination select box on resource's index page
 
+You can do it globally by setting the following line in the activeadmin initializer (config/initializers/active_admin.rb).
 
+```ruby
+config.default_per_page = [20, 50, 100, 200, 500]
+```
+
+Or per resource by registering in the resource the following:
+
+```ruby
+ActiveAdmin.register MyModel do
+  config.per_page = [20, 50, 100, 200]
+end
+```
+
+The numbers in the arrays are the options for the __per_page__ params.
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