O Di

def card_params
  params.require(:card).permit(:original_text, :translated_text, :review_date, :image, :deck_id, deck: [:title]).deep_merge(deck: {user_id: current_user.id})
end

def self.create_with_deck(params)
  deck_params = params.delete(:deck)
  if params[:deck_id].blank?
    deck = Deck.create(deck_params)
    params.deep_merge!(deck_id: deck[:id])
  end
  create(params)
end

• Изучил ли я документацию к использумой технологии?
  
• Потратил ли я несколько часов на чтение исходников или решение проблемы каким-нибудь ещё путём?
  
• Проверил ли я гугл на наличие нужной информации?
  

class Task < ActiveRecord::Base

  include AASM

  aasm :column => 'status' do
    state :in_work, :initial => true
    state :completed

    event :run do
      transitions :from => :completed, :to => :in_work
    end

    event :complete do
      transitions :from => :in_work, :to => :completed
    end
  end

class TasksController < ApplicationController
  before_action :find_task, only: [:show, :edit, :update, :destroy, :run, :complete]
  def run
    @task.run!
    redirect_to tasks_path
  end
  def complete
    @task.complete!
    redirect_to tasks_path
  end

<% @tasks.each do |task| %>
    <% if task.in_work? %>
      <%= link_to 'Complete', complete_task_path(task), method: :put %>
    <% else %>
      <%= link_to 'Run', run_task_path(task), method: :put %>
    <% end %>
<% end %>

resources :tasks do
    member do
      put :run
      put :complete
    end
  end

class Task < ActiveRecord::Base
  has_many    :subtasks, class_name: 'Task', foreign_key: "parent_id"
  belongs_to  :parent, class_name: 'Task'
  accepts_nested_attributes_for :subtasks, allow_destroy: true
  belongs_to  :user
  belongs_to  :project
end

def task_params
  params.require(:task).permit(:title, :description, :priority, :status, :scheduled, :deadline, subtasks_attributes: [:title])
end

<%= simple_form_for @task do |t| %>
  <%= t.simple_fields_for :subtasks, @task.subtasks.build do |f| %>
    <div class="form-inputs">
      <%= f.input :title %> 
    </div>
    <div class="form-actions">
      <%= f.button  :submit %>
    </div>
  <% end %>
<% end %>