Adding Role dynamically through Form USing Rolify along with Devise and Cancan

I just followed the tutorial "https://github.com/EppO/rolify/wiki/Tutorial" its very nice and working fine. But my question can't we add Role through form with out using Rails console.

<%= f.fields_for :users do |user_form| %>
    <div class="field"><%= user_form.label :email %><br />
    <%= user_form.email_field :email %></div>
    <div class="field"><%= user_form.label :password %><br />
    <%= user_form.password_field :password %></div>
    <div class="field"><%= user_form.label :password_confirmation %><br />
    <%= user_form.password_field :password_confirmation %></div>
    <div class="field">
      <%= f.label :roles %>
      <div class="controls">
        <% Role.all.each do |role| %>
          <%= check_box_tag "user[role_ids][]", role.id, @user.role_ids.include?(role.id) %>
          <%= role.name %><br />
        <% end %>
      </div>
    </div>
<% end %>

The Role column connect to roles table (Rolify Roles)

Here is my role.rb

class Role < ActiveRecord::Base

  has_and_belongs_to_many :users, :join_table => :users_roles

  belongs_to :resource, :polymorphic => true

User.rb

class User < ActiveRecord::Base

  belongs_to :account, :inverse_of => :users

  validates :account, :presence => true

  rolify

   attr_accessible :role_ids
   
  # Include default devise modules. Others available are:
  # :confirmable, :lockable, :timeoutable and :omniauthable

  devise :database_authenticatable, :registerable, :recoverable, :rememberable, :trackable, :validatable

  # Setup accessible (or protected) attributes for your model


  attr_accessible :email, :password, :password_confirmation, :remember_me, :role_ids

  # attr_accessible :title, :body

  has_many :auditinits
end

Any help is appreciate!!

In User Form, make a Drop down select for the roles as,

<%= user_form.select :role,options_from_collection_for_select(Role.all,"name","name) %>

Modify Create action in Users Controller as

@user = User.new(user_params)

@user.add_role params[:user][:role]