Generated migration for namespaced model prefixes table name

When generating a namespaced model the migration prefixes the table name with the namespace even though current Rails behaviour is to only prefix a table name when nested inside another AR model. e.g:

script/generate model Admin::User

generates:

class CreateAdminUsers < ActiveRecord::Migration
  def self.up
    create_table :admin_users do |t|

      t.timestamps
    end
  end

  def self.down
    drop_table :admin_users
  end
end

I've not got a patch at the moment because I can't decide where the problem should be fixed or what the correct behavior should be. I was investigating #2262 Associations are picking the wrong class so I'm just logging the problem for now to build up a list of issues with namespaced models with the aim of building a bunch of failing tests.