= form_for @ad do |f|
      - if ad.errors.any?
        #error_explanation
          h2
            = pluralize(ad.errors.count, "error")
            | prohibited this ad from being saved:
          ul
            - ad.errors.full_messages.each do |message|
              li= message
      = f.label :locality, "City, country", class: "field-label"
      = f.text_field :locality, class: "input field w-input", placeholder: "Ex: Paris, France", label: false

      = f.label :title,  "Job title :", class: "field-label"
      = f.text_field :title , class: "input field w-input", placeholder: "Ex :  Solidity Developer Expert...", label: false

      ...

      h3.h3.post The company
      = f.fields_for :company do |c|
        .w-row
          .w-col.w-col-6
            = c.label :name, "Company name", class: "field-label"
            = c.text_field :name, id: "salary-2", class: "field w-input", placeholder: "Ex : CryptoLimbo", label: false
          .w-col.w-col-6

            = c.label :email, "Company email", class: "field-label"
            = c.text_field :email, id: "salary-2", class: "field w-input", placeholder: "Ex : me@cryptolimbo.io", label: false

      ...

def create
    @ad = Ad.new(ad_params)
    company = Company.find_or_initialize_by(name: params[:ad][:company_attributes][:name])
    @ad.company_id = company.id

    if @ad.valid?
      @ad.save
      redirect_to root_path
      send_notifications(@ad)
    else
      flash[:error] = 'one or more errors in your job'
      render :new
    end
  end

   def update
    respond_to do |format|
      if @ad.update(ad_params)

        format.html { redirect_to @ad, notice: 'Ad was successfully updated.' }
        format.json { render :show, status: :ok, location: @ad }
      else
        format.html { render :edit }
        format.json { render json: @ad.errors, status: :unprocessable_entity }
      end
    end
  end

 private

 def ad_params
    params.require(:ad).permit(:title, :locality, ...,
        company_attributes: [:name, :id, :logo, :logo_cache, :short_description, :long_description, :twitter, :email ]
        )
end