Rails nested model form with has_one and has_many inside - ruby-on-rails

Question

I am using a nested form with has_one and a has_many relation inside it. The problem is that the data in the association is not being saved.
Below are the models, controller and the view I am using
Sell Order Model
class SellOrder < ActiveRecord::Base
belongs_to :company
has_one :work_order, dependent: :destroy
accepts_nested_attributes_for :work_order, :reject_if => lambda { |a| a[:content].blank? }, :allow_destroy => true
end
Work Order Model
class WorkOrder < ActiveRecord::Base
belongs_to :sell_order
has_many :todos, dependent: :destroy
accepts_nested_attributes_for :todos, :reject_if => lambda { |a| a[:content].blank? }, :allow_destroy => true
end
Todo Model
class Todo < ActiveRecord::Base
belongs_to :work_order
end
Sell Order Controller
class SellOrdersController < ApplicationController
def new
#sell_order = SellOrder.new(user: current_user)
1.times {
#work_order = #sell_order.build_work_order
#work_order.todos.build
}
end
def create
#sell_order = current_company.sell_orders.new(sell_order_params)
if #sell_order.save
redirect_to [:edit, #sell_order]
else
1.times {
#work_order = #sell_order.build_work_order
#work_order.todos.build
}
render :new
end
end
private
def sell_order_params
params.require(:sell_order).permit(:some_other_attributes, work_order_attributes: [todos_attributes: [:comment, :price]])
end
end
View
= f.fields_for :work_order do |builder_work_order|
= builder_work_order.fields_for :todos do |builder|
= builder.text_field :comment, class: 'form-control'
= builder.text_field :price, class: 'form-control'
When I submit the form, only the Sell Order is saved. No data goes in work order and todo tables. Does anyone has a solution for this type of situation?
Rails version: 4.1.1
Thanks in advance.