Devise + CanCan: Admin manages Users - ruby-on-rails

Question

With my set up I have 2 types of Devise users Admins and Users I would like to be able to have the admins manage the users.
I have found some tutorials about this but they approach the problem from the perspective of a single User model with roles.
So far I've gotten to the point where, when I'm logged in as an admin, I can list the users, destroy the users and create new users, however, when I try to edit a user I get a blank form (as opposed to one that's populated by user information)
Any advice would be appreciated.
Below are the relevant files. Let me know if you need to see anything else.
/config/routes.rb
TestApp::Application.routes.draw do
devise_for :admins
devise_for :users
root to: 'pages#home'
# Admin Routes
if Rails.env.production?
devise_for :admins, :skip => [:registrations]
else
devise_for :admins
end
namespace :admins do
resources :users
end
authenticated :admin do
# For production because of skip registrations
get 'admins/edit' => 'devise/registrations#edit', as: :edit_admin_registration
put 'admins' => 'devise/registrations#update', as: :admin_registration
get 'admins/dashboard' => 'admins#dashboard', as: :admin_dashboard
devise_scope :admin do
get 'admins/list' => 'admins/users#index', as: :manage_users
get 'admins/users/new' => 'admins/users#new', as: :new_admins_user
get 'admins/users/:id/edit' => 'admins/users#edit', as: :edit_admins_user
post 'admins/users' => 'admins/users#create', as: :users
delete 'admins/users/:id' => 'admins/users#destroy', as: :destroy_admins_user
end
# Manage Content Routes
get '/pages/manage' => 'pages#manage', as: :manage_pages
get '/products/manage' => 'products#manage', as: :manage_products
end
authenticated :user, :admin do
get '/products' => 'products#index'
get '/pages/4' => 'products#index'
get '/gallery' => 'products#index'
end
unauthenticated do
devise_scope :users do
get '/pages/4' => 'devise/registrations#new'
get '/gallery' => 'devise/registrations#new'
end
end
resources :pages
resources :products
end
/controllers/admins_controller.rb
class AdminsController < ApplicationController
load_and_authorize_resource
def dashboard
render "admins/dashboard"
end
def index
respond_to do |format|
format.html
end
end
def destroy
#admin.destroy
redirect_to manage_admins_path
end
end
/controllers/admins/users_controller.rb
class Admins::UsersController < ApplicationController
load_and_authorize_resource
def index
#users = User.all
respond_to do |format|
format.html
end
end
def new
#resource = User.new
respond_to do |format|
format.html
end
end
def edit
#user = User.find(params[:id])
end
def create
#user = User.new(params[:user])
respond_to do |format|
if #user.save
format.html { redirect_to manage_users_path, notice: 'User was successfully created.' }
else
format.html { render new_admin_user_path }
end
end
end
def update
#user = User.find(params[:id])
if params[:user][:password].blank?
params[:user].delete(:password)
params[:user].delete(:password_confirmation)
end
respond_to do |format|
if #user.update_attributes(params[:user])
format.html { redirect_to manage_users_path, notice: 'User was successfully updated.' }
else
format.html { render action: "edit" }
end
end
end
def destroy
#user = User.find(params[:id])
#user.destroy
redirect_to manage_users_path
end
# private
# def check_permissions
# authorize! :create, resource
# end
end
/views/admins/users/edit.html.haml
.input-form
%h2
Edit #{resource_name.to_s.humanize}
= form_for(resource, :as => resource_name, :url => registration_path(resource_name), :html => { :method => :put }) do |f|
= devise_error_messages!
%fieldset{id: "edit-your-account"}
.field.required
= f.label :first_name
= f.text_field :first_name, :autofocus => true
.field.required
= f.label :last_name
= f.text_field :last_name
.field.required
= f.label :company
= f.text_field :company
.field.required
= f.label :phone
= f.text_field :phone
.field.required
= f.label :email
= f.email_field :email
.field.required
= f.label :password
= f.password_field :password
%span.instructions
(leave blank if you don't want to change it)
- if devise_mapping.confirmable? && resource.pending_reconfirmation?
%br
Currently waiting confirmation for:
= resource.unconfirmed_email
.field.required
= f.label :password_confirmation
= f.password_field :password_confirmation
.field.required
= f.label :current_password
= f.password_field :current_password
%span.instructions
(we need your current password to confirm your changes)
.field
= f.submit "Update"
= link_to "Back", :back
/helpers/admins_helper.rb
module AdminsHelper
# Devise helpers for Admin::UsersController
def resource_name
:user
end
def resource
#resource ||= User.new
end
def devise_mapping
#devise_mapping ||= Devise.mappings[:user]
end
end

Answer 1

Looks like renaming your instance variable should do the trick. Your edit template passes the object resource to the form but the object you've loaded from the database is set to #user:
# Admins::UsersController
def edit
#user = User.find(params[:id])
end
# AdminsHelper
def resource
#resource ||= User.new
end
You could pass this instance variable to the form_for instead, or rename #user as #resource so the helper method will return the proper instance.