Error and form data

undefined method `each' for "true":String

{"utf8"=>"✓",
 "_method"=>"put",
 "authenticity_token"=>"TTCSyAiy98vRZOKQDljKlkHYxRiLKBSnhL0iGUVMUq8=",
 "shared_produit"=>{"shared"=>"true"},
 "commit"=>"Autoriser partage",
 "locale"=>"fr",
 "produit_id"=>"37"}

Form

= semantic_form_for @produit.shared_produit, :url => url_for(:controller =>"backend/shared_produits", :action =>"update",:produit_id=>@produit.id),:method=>:put do |f|
        = f.input :shared, :input_html => { :value => true}, :as=>:hidden
        = f.submit "Autoriser partage"

Model

class SharedProduit < ActiveRecord::Base
  include ActiveModel::ForbiddenAttributesProtection
  # attr_accessible :good_id, :owner, :shared, :sharing_start
  belongs_to :good
  validate
  belongs_to :owner, :class_name =>'Shop',:foreign_key => "owner_id"
  has_many :shared, :class_name =>'Produit',:foreign_key => "shared_from_id"
  validates_presence_of :good
  before_save :set_owner_id

  private

  def set_owner_id
    self.owner=self.good.shop
  end
end

Strong params

def shared_produit_params
    if current_admin_user.admin
      params.require(:shared_produit).permit(:sharing_start,:free_price,:shared)
    else
      params.require(:shared_produit).permit(:sharing_start,:free_price,:shared)
    end
  end

Update action

def update
    @produit=Produit.updatable_to(current_admin_user,current_shop).find(params[:produit_id])
    @[email protected]_produit
    if @shared_produit.update_attributes(shared_produit_params)
      redirect_to :back, notice: "Partage modifié"
    else
      redirect_to :back,  alert: "Erreur lors de l'édition"
    end
  end