Active Admin Impersonate

  # within app/admin/users.rb

  member_action :impersonate, :method => :get do
    user = User.find(params[:id])
    begin
      flash[:notice] = "Successfully logged in as : #{user.email} #{view_context.link_to('Be careful!', root_path)}".html_safe
      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(:impersonate, only: :show) do
    link_to('Impersonate', impersonate_admin_user_path(resource))
  end