Problem with accepts_nested_attributes devise rails 5

I am implementing a user registry with Devise 4.3.0 in Rails 5.1.3. Each user belongs to a Community and if the name of the community is provided in the registry a new community must be created next to the user.

The models:

class User < ApplicationRecord
  # Include default devise modules. Others available are:
  # :confirmable, :lockable, :timeoutable and :omniauthable
  devise :database_authenticatable, :registerable,
         :recoverable, :rememberable, :trackable, :validatable
  belongs_to :community, optional: true
  accepts_nested_attributes_for :community
end

class Community < ApplicationRecord
    has_many :users
end

I have created a driver for user registration:

class User::RegistrationsController < ::Devise::RegistrationsController
  before_action :configure_sign_up_params, only: [:create]
  before_action :configure_community_update_params, only: [:update]

  # GET /resource/sign_up
  def new
     super
       resource.build_community
       logger.info('-------NEW REGISTRATION')
       logger.info(resource.community_id)
  end

  # POST /resource
   def create
     super
   end

  protected

  # If you have extra params to permit, append them to the sanitizer.
  def configure_sign_up_params
    devise_parameter_sanitizer.permit(:sign_up, keys: [community_attributes: [:name]])
  end

  # If you have extra params to permit, append them to the sanitizer.
  def configure_community_update_params
   devise_parameter_sanitizer.permit(:sign_up, keys: [:name])
  end
end

In the custom view I include a form for the community:

<h2>Sign up</h2>

<%= form_for(resource, as: resource_name, url: registration_path(resource_name)) do |f| %>
  <%= devise_error_messages! %>

  <div class="field">
    <%= f.label :email %><br />
    <%= f.email_field :email, autofocus: true %>
  </div>

  <div class="field">
    <%= f.label :password %>
    <% if @minimum_password_length %>
    <em>(<%= @minimum_password_length %> characters minimum)</em>
    <% end %><br />
    <%= f.password_field :password, autocomplete: "off" %>
  </div>

  <div class="field">
    <%= f.label :password_confirmation %><br />
    <%= f.password_field :password_confirmation, autocomplete: "off" %>
  </div>


  <p> Comunidad </p>

  <%= f.fields_for :community do |c| %>
    <%= c.label :community_name %><br />
    <%= c.text_field :name %>
  <% end %>

  <div class="actions">
    <%= f.submit "Sign up" %>
  </div>
<% end %>

<%= render "devise/shared/links" %>

The problem I have is that the text box is not shown in the view and I have doubts about whether it would be correctly associated with the user even if it were displayed.

If you try to create a user, it is created correctly but without associating any Community. The log shows the following:

    Started GET "/users/sign_up" for 127.0.0.1 at 2018-02-21 11:50:22 +0100
Processing by User::RegistrationsController#new as HTML
  Rendering devise/registrations/new.html.erb within layouts/application
  Rendered devise/shared/_links.html.erb (24.0ms)
  Rendered devise/registrations/new.html.erb within layouts/application (88.0ms)

-------NEW REGISTRATION

Completed 200 OK in 1972ms (Views: 1760.1ms | ActiveRecord: 11.0ms)

Started POST "/users" for 127.0.0.1 at 2018-02-21 11:50:42 +0100
Processing by User::RegistrationsController#create as HTML
  Parameters: {"utf8"=>"V", "authenticity_token"=>"C8c090OppHEve2JyNR+exuwmLNYtT
EaT11+6WUERwNs4DupDg+wWtLgdzmaPudgRCXEH/PpwHCzwSrk7g2RkhA==", "user"=>{"email"=>
"[email protected]", "password"=>"[FILTERED]", "password_confirmation"=>"[FILTERED]"}, "commit"=>"Sign up"}
   (77.0ms)  begin transaction
  User Exists (0.0ms)  SELECT  1 AS one FROM "users" WHERE "users"."email" = ? LIMIT ?  [["email", "[email protected]"], ["LIMIT", 1]]
  SQL (19.0ms)  INSERT INTO "users" ("email", "encrypted_password", "created_at"
, "updated_at") VALUES (?, ?, ?, ?)  [["email", "[email protected]"], ["encrypte
d_password", "$2a$11$OXep2cdfnXVJJOBT2CKKx.mBPULbonEO/qtCfaYHBd5v3zfjT55iq"], ["
created_at", "2018-02-21 10:50:44.205807"], ["updated_at", "2018-02-21 10:50:44.
205807"]]
   (174.0ms)  commit transaction
   (0.0ms)  begin transaction
  SQL (23.0ms)  UPDATE "users" SET "sign_in_count" = ?, "current_sign_in_at" = ?
, "last_sign_in_at" = ?, "current_sign_in_ip" = ?, "last_sign_in_ip" = ?, "updated_at" = ? WHERE "users"."id" = ?  [["sign_in_count", 1], ["current_sign_in_at",
 "2018-02-21 10:50:44.870845"], ["last_sign_in_at", "2018-02-21 10:50:44.870845"
], ["current_sign_in_ip", "127.0.0.1"], ["last_sign_in_ip", "127.0.0.1"], ["updated_at", "2018-02-21 10:50:44.916848"], ["id", 27]]
   (122.0ms)  commit transaction
Redirected to http://localhost:3000/
Completed 302 Found in 2864ms (ActiveRecord: 415.0ms)


Started GET "/" for 127.0.0.1 at 2018-02-21 11:50:45 +0100
Processing by WelcomeController#index as HTML
  Rendering welcome/index.html.erb within layouts/application
  Rendered welcome/index.html.erb within layouts/application (7.0ms)
  User Load (11.0ms)  SELECT  "users".* FROM "users" WHERE "users"."id" = ? ORDER BY "users"."id" ASC LIMIT ?  [["id", 27], ["LIMIT", 1]]
Completed 200 OK in 1264ms (Views: 1186.2ms | ActiveRecord: 11.0ms)

I have followed several guides and reviewed other similar problems but I can not move forward. Thanks.