[Rails] Resourceful routing and admin namespace question

Hi all. I have a route file like this:

Deals::Application.routes.draw do
root to: "Main#home"

resources :vendors do
resources :offers
end

match '/admin' => 'Admin::Pages#index'

namespace :admin do
match '/login', to: 'Sessions#new'
resources :offers, :vendors
resources :sessions, only: [:new, :create, :destroy]
end
end


First of all I would like to know if the way I declared the namespace and
the matching rules inside it are ok.

Next, I want the visitors of the app (front-end) to be able only to view
the :offers and :vendor resources (index & show actions). I only want to
allow admins (app.com/admin/blabla) which are the logged users, to be able
to manage these resources (edit, add, delete etc). How could I implement
this?

Should I do it like this? http://pastie.org/3503560 Or could I just leave
it as is and not implement the actions in the public controllers?