title: Devise User can't be edited
body: <p>I have a Rails app using Devise for user authentication. I'm pretty sure the Devise edit user feature worked previously, but for some reason, edit/update doesn't work anymore. When I click "Update", the page just refreshes on the form. It also displays "Please review the problems below:" even though I've entered everything correctly. </p>
  
  <p>The cancel account function works perfectly, however. Could the issue be the url path? If so, why does canceling the account work, while updating doesn't? I do have the user model nested within another model, but I've tried variations on the url path, none of which have worked.</p>
  
  <p>Below is the form page generated by Devise and using simple_form:</p>
  
  <pre><code>.col-md-5.col-md-offset-2
    %h2
      Edit #{resource_name.to_s.humanize}
    = simple_form_for(resource, as: resource_name, url: registration_path(resource_name)    , html: { method: :put }) do |f|
      = f.error_notification
      .form-inputs
        = f.input :email, required: true, autofocus: true
        - if devise_mapping.confirmable? &amp;&amp; resource.pending_reconfirmation?
          %p
            Currently waiting confirmation for: #{resource.unconfirmed_email}
        = f.input :password, autocomplete: "off", hint: "leave it blank if you don't     want to change it", required: false
        = f.input :password_confirmation, required: false
        = f.input :current_password, hint: "we need your current password to confirm     your changes", required: true
      .form-actions
        = f.button :submit, "Update"
    %h3 Cancel my account
    %p
      Unhappy? #{link_to "Cancel my account", registration_path(resource_name), data: {     confirm: "Are you sure?" }, method: :delete}
    = link_to "Back", root_path
  </code></pre>
  
  <p><strong>Update:</strong></p>
  
  <p>Here's the printout from development.log:</p>
  
  <pre><code>Started PUT "/users" for 127.0.0.1 at 2014-12-14 00:05:07 -0500
  Processing by Users::RegistrationsController#update as HTML
    Parameters: {"utf8"=&gt;"✓", "authenticity_token"=&gt;"Zhtv8rbmwIDuZO7Tv/0db7tSIGfGUEW56fqPKzkgQSo=", "user"=&gt;{"email"=&gt;"test3@test3.com", "password"=&gt;"[FILTERED]", "password_confirmation"=&gt;"[FILTERED]", "current_password"=&gt;"[FILTERED]"}, "commit"=&gt;"Update"}
    [1m[36mUser Load (0.3ms)[0m  [1mSELECT  `users`.* FROM `users`  WHERE `users`.`id` = 16  ORDER BY `users`.`id` ASC LIMIT 1[0m
    [1m[35mUser Load (0.2ms)[0m  SELECT  `users`.* FROM `users`  WHERE `users`.`id` = 16 LIMIT 1
    [1m[36m (0.2ms)[0m  [1mBEGIN[0m
    [1m[35m (0.1ms)[0m  ROLLBACK
    Rendered devise/registrations/edit.html.haml within layouts/application (4.3ms)
    Rendered common/_login.html.haml (0.5ms)
  Completed 200 OK in 328ms (Views: 175.1ms | ActiveRecord: 0.7ms)
  </code></pre>
  
  <p>Here's my routes.rb file. I do have Users listed twice.</p>
  
  <pre><code>devise_for :users
  
  root 'welcome#index'
  
  resources :wedding_checklists do
    resources :users
    resources :checklist_items
  end
  </code></pre>