Active Admin User Impersonation

gistfile1.rb

ActiveAdmin.register User do
  menu :parent => "Users"

  member_action :impersonate, :method => :get do
    user = User.find(params[:id])
    flash[:notice] = "Successfully logged in as : #{user.email} #{view_context.link_to('Be careful!', root_path)}".html_safe
    begin
      warden.set_user(resource,{:scope=>:user,:run_callbacks=>false})
    rescue
      flash[:error] = "Unable to log you in.  Poop."
    end
    redirect_to admin_users_path
  end

  action_item :only => :show do
    link_to('Impersonate', impersonate_admin_user_path(resource))
  end

  index do
    column :id
    column :email
    column :created_at
    column :current_sign_in_at
    column :last_sign_in_at
    column :completed_wizard
    
    column "Special" do |resource|
      link_to("Impersonate", impersonate_admin_user_path(resource), :class => "member_link edit_link")
    end
    default_actions
  end
  form do |f|
    f.inputs "User Details" do
      f.input :email
    end
    f.buttons
  end
end