How to make rails associations work

I have this set up, but noting gets saved to the db when I try to save a practitioner.
The tables are users, clinics and practitioners. The user should be able to create multiple clinics and each clinic should be able to add multiple practitioners to the specific clinic.

I can't seem to figure out, what I should do to make it work. I can see it says that user.rb is missing practitioners_attribute
but practitioners is associated to clinic and not user, that's why I've put it in clinic.rb, and even if I put accepts_nested_attributes_for :practitioners, reject_if: :all_blank, allow_destroy: true in user.rb it still doesn't work.

I get this error:
ActiveModel::UnknownAttributeError in RegistrationStepsController#update
unknown attribute 'practitioners_attributes' for User.
@user = current_user
# Change @user.attributes(user_params) by @user.update_attributes(user_params)
@user.update_attributes(user_params)
render_wizard @user
end

This is how I have tried to make it work so far:

User has many clinics

clinics belongs to user

clinics has many practitioners

practitioners belongs to clinics

I’ve added a foreign user key to connect clinics table with users table

I’ve added a foreign clinic key to connect practitioners table with clinics table

user.rb

class User < ApplicationRecord        
has_many :clinics, dependent: :destroy
accepts_nested_attributes_for :clinics, reject_if: :all_blank, allow_destroy: true
end

clinic.rb

class Clinic < ApplicationRecord
belongs_to :user
has_many :practitioners
    accepts_nested_attributes_for :practitioners, reject_if: :all_blank, allow_destroy: true
end

practitioner.rb

class Practitioner < ApplicationRecord
belongs_to: clinic
end

add clinics foreign key to practitioners

class AddClinicReferenceToPratitioners < ActiveRecord::Migration[5.2]
def change
add_reference :practitioners, :clinic, foreign_key: true
end
end

add users foreign key to clinics

class AddUserReferenceToClinics < ActiveRecord::Migration[5.2]
def change
add_reference :clinics, :user, foreign_key: true
end
end

practitioners_general.html.rb

<div class="content">
<div class="content practitioner">
<h2 class="page-title">Generel information</h2>

<%= simple_form_for @user, url: wizard_path, method: :put do |f| %>

<%= f.simple_fields_for(:practitioners) do |p| %>
<%= render 'practitioners/practitioners_fields', :f => p %>
<% end %>
</div>
<div class="submit-container">
<%= f.submit "Gem", :class => 'btn blue' %>

</div>
<% end %>

</div>

practitioners_fields.html.erb

<div class="nested-fields">
  <div class="basic-section">

    <div class="info-group">
      <div class="field-group">
        <div class="field text-field">

          <%= f.input_field :practitioner_first_name, required: true, autofocus: true, autocomplete: "Fornavn", placeholder: "Fornavn" %>
        </div>
        <div class="field text-field">
          <%= f.input_field :practitioner_last_name, required: true, autofocus: true, autocomplete: "Efternavn", placeholder: "Efternavn" %>
        </div>
      </div>

    </div>
  </div>
  <div class="about-section">
    <div class="field text-field">
      <%= f.input_field :practitioner_description, :as => :text, :input_html => { 'rows' => 5}, autofocus: true, autocomplete: "Beskrivelse af behandler", placeholder: "Beskrivelse af behandler" %>
    </div>

  </div>
  <div class="field-group contact-section">
    <div class="field text-field">
      <%= f.input_field :practitioner_mail, input_html: { autocomplete: 'email' }, autofocus: true, placeholder: "E-mail" %>
    </div>
    <div class="field text-field">
      <%= f.input_field :practitioner_phone, autofocus: true, autocomplete: "Tlf. nr.", placeholder: "Tlf. nr." %>
    </div>
    <div class="field text-field">
      <%= f.input_field :practitioner_website, required: false, autofocus: true, autocomplete: "Hjemmeside", placeholder: "Hjemmeside" %>
    </div>
  </div>

</div>

registration_steps_controller.rb

class RegistrationStepsController < ApplicationController

    include Wicked::Wizard
    steps :company_general, :company_images, :practitioners_general, :practitioners_professions, :practitioners_educations

    def create
      @practitioner = Practitioner.new(params[:practitioners])
      @practitioner.save
    end

    def show
     @user = current_user    
    render_wizard 
    end

    def update
      @user = current_user
      # Change @user.attributes(user_params) by @user.update_attributes(user_params)
      @user.update_attributes(user_params)
      render_wizard @user
    end



private
def user_params
  params.require(:user)
  .permit(:gender, :first_name, :last_name, :email, :password, :password_confirmation, :phone, 
    :clinic_logo, 
    :practitioner_image,
    :public_health_insurance, 
    clinic_images: [], 
    profession_ids: [], 
    speciality_ids: [], 
    services_attributes: [:id, :description, :name, :duration, :price, :_destroy], 
    educations_attributes: [:id, :name, :place, :year, :_destroy],
    membership_ids: [],
    awards_attributes: [:id, :name, :year, :_destroy],
    clinics_attributes: [:id, :clinic_logo, :clinic_name, :clinic_address, :clinic_zip_code, :clinic_municipality, :clinic_about, :clinic_mail, :clinic_phone, :clinic_website, :clinic_city, :_destroy],
    practitioners_attributes: [:id, :practitioner_first_name, :practitioner_last_name, :practitioner_description, :practitioner_mail, :practitioner_phone, :practitioner_website, :_destroy])

end

end

ApplicationController.rb

class ApplicationController < ActionController::Base
  protect_from_forgery with: :exception

    before_action :authenticate_user!, :configure_permitted_parameters, if: :devise_controller?

    protected

    def configure_permitted_parameters
      devise_parameter_sanitizer.permit(:sign_up, keys: 
        [:gender, :first_name, :last_name, :email, :password, :password_confirmation, :phone, 
        :clinic_logo, 
        :practitioner_image,
        :public_health_insurance, 
        clinic_images: [], 
        profession_ids: [], 
        speciality_ids: [], 
        services_attributes: [:id, :description, :name, :duration, :price, :_destroy], 
        educations_attributes: [:id, :name, :place, :year, :_destroy],
        membership_ids: [],
        awards_attributes: [:id, :name, :year, :_destroy],
        clinics_attributes: [:id, :clinic_logo, :clinic_name, :clinic_address, :clinic_zip_code, :clinic_municipality, :clinic_about, :clinic_mail, :clinic_phone, :clinic_website, :clinic_city, :_destroy],
        practitioners_attributes: [:id, :practitioner_first_name, :practitioner_last_name, :practitioner_description, :practitioner_mail, :practitioner_phone, :practitioner_website, :_destroy]])


        devise_parameter_sanitizer.permit(:account_update, keys: 
          [:gender, :first_name, :last_name, :email, :password, :password_confirmation, :phone, 
            :clinic_logo, 
            :practitioner_image, 
            :public_health_insurance, 
            clinic_images: [], 
            profession_ids: [], 
            speciality_ids: [], 
            services_attributes: [:id, :description, :name, :duration, :price, :_destroy], 
            educations_attributes: [:id, :name, :place, :year, :_destroy],
            membership_ids: [],
            awards_attributes: [:id, :name, :year, :_destroy],
            clinics_attributes: [:id, :clinic_logo, :clinic_name, :clinic_address, :clinic_zip_code, :clinic_municipality, :clinic_about, :clinic_mail, :clinic_phone, :clinic_website, :clinic_city, :_destroy],
            practitioners_attributes: [:id, :practitioner_first_name, :practitioner_last_name, :practitioner_description, :practitioner_mail, :practitioner_phone, :practitioner_website, :_destroy]])



    end


    def after_sign_in_path_for(resource)
      rails_admin_path
    end

  end

routes.rb

Rails.application.routes.draw do
  mount RailsAdmin::Engine => '/admin', as: 'rails_admin'

  devise_for :users, controllers: {:registrations => "users/registrations" 
  }

  resources :registration_steps
  # For details on the DSL available within this file, see http://guides.rubyonrails.org/routing.html
  root 'pages#index' 
  get 'about', to: 'pages#about'
  get 'team', to: 'pages#team'
  get 'faqs', to: 'pages#faqs'
  get 'faqspractitioners', to: 'pages#faqspractitioners'
  get 'faqsusers', to: 'pages#faqsusers'
  get 'login', to: 'pages#login'
  get 'signup', to: 'pages#signup'
  get 'search', to: 'pages#search'


  get "userprofiles/user_info" => "userprofiles#user_info", as: "user_info"
  get "userprofiles/clinic_info" => "userprofiles#clinic_info", as: "clinic_info"
  get "userprofiles/practitioner_info" => "userprofiles#practitioner_info", as: "practitioner_info"


  patch "userprofiles/user_info" => "userprofiles#update"
  patch "userprofiles/clinic_info" => "userprofiles#update"
  patch "userprofiles/practitioner_info" => "userprofiles#update"


  devise_scope :user do 
    scope module: :users do
      resources :registrations, only: [] do
        member do
          delete :delete_image_attachment
        end
      end
    end
  end

end

I fixed it by changing the params from

    clinics_attributes: [:id, :clinic_logo, :clinic_name, :clinic_address, :clinic_zip_code, :clinic_municipality, :clinic_about, :clinic_mail, :clinic_phone, :clinic_website, :clinic_city, :_destroy],
        practitioners_attributes: [:id, :practitioner_first_name, :practitioner_last_name, :practitioner_description, :practitioner_mail, :practitioner_phone, :practitioner_website, :_destroy])

end

to

clinics_attributes: [:id, :clinic_logo, :clinic_name, :clinic_address, :clinic_zip_code, :clinic_municipality, :clinic_about, :clinic_mail, :clinic_phone, :clinic_website, :clinic_city, :_destroy,
    practitioners_attributes: [:id, :practitioner_first_name, :practitioner_last_name, :practitioner_description, :practitioner_mail, :practitioner_phone, :practitioner_website, :_destroy]])

end