Active admin action item/member action

This can be done with the following:

ActiveAdmin.register Post do
  index do
    column :name
    actions defaults: true do |post|
      link_to 'Archive', archive_admin_post_path(post)
    end
  end
end

Note that using defaults: true will append your custom actions to active admin default actions.

For the friend who landed the page, In order to append more than 1 link

Do Something Like:

    actions default: true do |model|
        [
            link_to('Option 1', "#"),
            '  ',
            link_to('Option 2', "#")
        ].reduce(:+).html_safe
    end

Found an answer here. You can do it using the below code with the code from the question (removing the action item block)

index do
...
  actions do |subscription|
    link_to('Approve', approve_admin_subscription_path(subscription))
  end
...
end

But I think there is a way to do it by appending an action to the default actions (so if you know how to do that, then add another answer!)

Additionally to remove the defaults you can change it like it is here:

actions :defaults => false do |subscription|