Первый аргумент в форме не может содержать nil или быть пустым при попытке создать вложенный ресурс в ruby ​​on rails

В своем приложении я пытаюсь создать вложенный ресурс (шаг для заданной цели), и у меня возникают проблемы с созданием по URL-адресу «/goals/1/steps/new». Когда я перехожу на эту страницу, я получаю сообщение об ошибке "Первый аргумент в форме не может содержать nil или быть пустым"

Я действительно не могу понять, почему я не могу создать шаг, который при создании назначается конкретному, для которого он был создан. Любая помощь приветствуется.

Ниже мой контроллер шагов и моя форма шагов

Контроллер шагов:

    class StepsController < ApplicationController
      #before_action :set_step, only: [:show, :edit, :update, :destroy]
      before_filter :authorize

      # GET /steps
      # GET /steps.json
      def index 
        @steps = Goal.find(params[:goal_id]).steps.all
      end 

      # GET /goals/1/steps/new
      def new
        @step = Goal.find(params[:goal_id]).steps.new 
      end 

      # GET /steps/1
      # GET /steps/1.json
      def show
      end

      # GET /steps/1/edit
      def edit
      end

      def create 
        @step = Goal.find(params[:goal_id]).steps.new(step_params)

        respond_to do |format|
          if @step.save
            format.html { redirect_to @step, notice: 'Step was successfully created.' }
            format.json { render :show, status: :created, location: @step }
          else
            format.html { render :new }
            format.json { render json: @step.errors, status: :unprocessable_entity }
          end
        end

        redirect_to(goal_steps_url(@goal))

      end 

      def update 
        @step.update(step_params)
        respond_to do |format|
          if @step.update(step_params)
            format.html { redirect_to @step, notice: 'Step was successfully updated.' }
            format.json { render :show, status: :ok, location: @step }
          else
            format.html { render :edit }
            format.json { render json: @step.errors, status: :unprocessable_entity }
          end
        end
      end 

      # POST /steps
      # POST /steps.json

      def destroy
        @step.destroy
        respond_to do |format|
          format.html { redirect_to steps_url, notice: 'Step was successfully destroyed.' }
          format.json { head :no_content }
        end
      end

      private

        def set_step 
          @step = Goal.find(params[:goal_id]).Step.find(params[:id])
        end 

        def step_params 
          params.require(:step).permit(:requirement, :completionTime, :goal_id) 
        end 

      end

Форма шагов:

    <%= form_for(@steps) do |f| %>
  <% if @step.errors.any? %>
    <div id="error_explanation">
      <h2><%= pluralize(@step.errors.count, "error") %> prohibited this step from being saved:</h2>

      <ul>
      <% @step.errors.full_messages.each do |message| %>
        <li><%= message %></li>
      <% end %>
      </ul>
    </div>
  <% end %>

  <div class="field">
    <%= f.label :requirement %><br>
    <%= f.text_field :requirement %>
  </div>
  <div class="field">
    <%= f.label :completionTime %><br>
    <%= f.number_field :completionTime %>
  </div>
  <div class="field">
    <%= hidden_field_tag :goal_id, goal.id %>
  </div>
  <div class="actions">
    <%= f.submit %>
  </div>
<% end %>

файл маршрутов:

Rails.application.routes.draw do

  resources :goals do
    resources :steps
  end

  resources :signups
  get 'welcome/index'

  resources :calendar

  resources :todolist

  resources :to_dos

  root 'welcome#index'

  # These routes will be for signup. The first renders a form in the browse, the second will 
  # receive the form and create a user in our database using the data given to us by the user.
  get '/login' => 'sessions#new'
  post '/login' => 'sessions#create'
  get '/logout' => 'sessions#destroy'

  get '/signup' => 'users#new'
  post '/users' => 'users#create'
end

Трассировки стека:

actionview (4.2.5.1) lib/action_view/helpers/form_helper.rb:432:in `form_for'
app/views/steps/_form.html.erb:1:in `_app_views_steps__form_html_erb__4323915558924223187_70260809990920'
actionview (4.2.5.1) lib/action_view/template.rb:145:in `block in render'
activesupport (4.2.5.1) lib/active_support/notifications.rb:166:in `instrument'
actionview (4.2.5.1) lib/action_view/template.rb:333:in `instrument'
actionview (4.2.5.1) lib/action_view/template.rb:143:in `render'
actionview (4.2.5.1) lib/action_view/renderer/partial_renderer.rb:339:in `render_partial'
actionview (4.2.5.1) lib/action_view/renderer/partial_renderer.rb:310:in `block in render'
actionview (4.2.5.1) lib/action_view/renderer/abstract_renderer.rb:39:in `block in instrument'
activesupport (4.2.5.1) lib/active_support/notifications.rb:164:in `block in instrument'
activesupport (4.2.5.1) lib/active_support/notifications/instrumenter.rb:20:in `instrument'
activesupport (4.2.5.1) lib/active_support/notifications.rb:164:in `instrument'
actionview (4.2.5.1) lib/action_view/renderer/abstract_renderer.rb:39:in `instrument'
actionview (4.2.5.1) lib/action_view/renderer/partial_renderer.rb:309:in `render'
actionview (4.2.5.1) lib/action_view/renderer/renderer.rb:47:in `render_partial'
actionview (4.2.5.1) lib/action_view/helpers/rendering_helper.rb:35:in `render'
app/views/steps/new.html.erb:3:in `_app_views_steps_new_html_erb__538834525682328601_70260798181140'
actionview (4.2.5.1) lib/action_view/template.rb:145:in `block in render'
activesupport (4.2.5.1) lib/active_support/notifications.rb:166:in `instrument'
actionview (4.2.5.1) lib/action_view/template.rb:333:in `instrument'
actionview (4.2.5.1) lib/action_view/template.rb:143:in `render'
actionview (4.2.5.1) lib/action_view/renderer/template_renderer.rb:54:in `block (2 levels) in render_template'
actionview (4.2.5.1) lib/action_view/renderer/abstract_renderer.rb:39:in `block in instrument'
activesupport (4.2.5.1) lib/active_support/notifications.rb:164:in `block in instrument'
activesupport (4.2.5.1) lib/active_support/notifications/instrumenter.rb:20:in `instrument'
activesupport (4.2.5.1) lib/active_support/notifications.rb:164:in `instrument'
actionview (4.2.5.1) lib/action_view/renderer/abstract_renderer.rb:39:in `instrument'
actionview (4.2.5.1) lib/action_view/renderer/template_renderer.rb:53:in `block in render_template'
actionview (4.2.5.1) lib/action_view/renderer/template_renderer.rb:61:in `render_with_layout'
actionview (4.2.5.1) lib/action_view/renderer/template_renderer.rb:52:in `render_template'
actionview (4.2.5.1) lib/action_view/renderer/template_renderer.rb:14:in `render'
actionview (4.2.5.1) lib/action_view/renderer/renderer.rb:42:in `render_template'
actionview (4.2.5.1) lib/action_view/renderer/renderer.rb:23:in `render'
actionview (4.2.5.1) lib/action_view/rendering.rb:100:in `_render_template'
actionpack (4.2.5.1) lib/action_controller/metal/streaming.rb:217:in `_render_template'
actionview (4.2.5.1) lib/action_view/rendering.rb:83:in `render_to_body'
actionpack (4.2.5.1) lib/action_controller/metal/rendering.rb:32:in `render_to_body'
actionpack (4.2.5.1) lib/action_controller/metal/renderers.rb:37:in `render_to_body'
actionpack (4.2.5.1) lib/abstract_controller/rendering.rb:25:in `render'
actionpack (4.2.5.1) lib/action_controller/metal/rendering.rb:16:in `render'
actionpack (4.2.5.1) lib/action_controller/metal/instrumentation.rb:44:in `block (2 levels) in render'
activesupport (4.2.5.1) lib/active_support/core_ext/benchmark.rb:12:in `block in ms'
/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/benchmark.rb:296:in `realtime'
activesupport (4.2.5.1) lib/active_support/core_ext/benchmark.rb:12:in `ms'
actionpack (4.2.5.1) lib/action_controller/metal/instrumentation.rb:44:in `block in render'
actionpack (4.2.5.1) lib/action_controller/metal/instrumentation.rb:87:in `cleanup_view_runtime'
activerecord (4.2.5.1) lib/active_record/railties/controller_runtime.rb:25:in `cleanup_view_runtime'
actionpack (4.2.5.1) lib/action_controller/metal/instrumentation.rb:43:in `render'
actionpack (4.2.5.1) lib/action_controller/metal/implicit_render.rb:10:in `default_render'
actionpack (4.2.5.1) lib/action_controller/metal/implicit_render.rb:5:in `send_action'
actionpack (4.2.5.1) lib/abstract_controller/base.rb:198:in `process_action'
actionpack (4.2.5.1) lib/action_controller/metal/rendering.rb:10:in `process_action'
actionpack (4.2.5.1) lib/abstract_controller/callbacks.rb:20:in `block in process_action'
activesupport (4.2.5.1) lib/active_support/callbacks.rb:117:in `call'
activesupport (4.2.5.1) lib/active_support/callbacks.rb:117:in `call'
activesupport (4.2.5.1) lib/active_support/callbacks.rb:555:in `block (2 levels) in compile'
activesupport (4.2.5.1) lib/active_support/callbacks.rb:505:in `call'
activesupport (4.2.5.1) lib/active_support/callbacks.rb:505:in `call'
activesupport (4.2.5.1) lib/active_support/callbacks.rb:92:in `__run_callbacks__'
activesupport (4.2.5.1) lib/active_support/callbacks.rb:778:in `_run_process_action_callbacks'
activesupport (4.2.5.1) lib/active_support/callbacks.rb:81:in `run_callbacks'
actionpack (4.2.5.1) lib/abstract_controller/callbacks.rb:19:in `process_action'
actionpack (4.2.5.1) lib/action_controller/metal/rescue.rb:29:in `process_action'
actionpack (4.2.5.1) lib/action_controller/metal/instrumentation.rb:32:in `block in process_action'
activesupport (4.2.5.1) lib/active_support/notifications.rb:164:in `block in instrument'
activesupport (4.2.5.1) lib/active_support/notifications/instrumenter.rb:20:in `instrument'
activesupport (4.2.5.1) lib/active_support/notifications.rb:164:in `instrument'
actionpack (4.2.5.1) lib/action_controller/metal/instrumentation.rb:30:in `process_action'
actionpack (4.2.5.1) lib/action_controller/metal/params_wrapper.rb:250:in `process_action'
activerecord (4.2.5.1) lib/active_record/railties/controller_runtime.rb:18:in `process_action'
actionpack (4.2.5.1) lib/abstract_controller/base.rb:137:in `process'
actionview (4.2.5.1) lib/action_view/rendering.rb:30:in `process'
actionpack (4.2.5.1) lib/action_controller/metal.rb:196:in `dispatch'
actionpack (4.2.5.1) lib/action_controller/metal/rack_delegation.rb:13:in `dispatch'
actionpack (4.2.5.1) lib/action_controller/metal.rb:237:in `block in action'
actionpack (4.2.5.1) lib/action_dispatch/routing/route_set.rb:74:in `call'
actionpack (4.2.5.1) lib/action_dispatch/routing/route_set.rb:74:in `dispatch'
actionpack (4.2.5.1) lib/action_dispatch/routing/route_set.rb:43:in `serve'
actionpack (4.2.5.1) lib/action_dispatch/journey/router.rb:43:in `block in serve'
actionpack (4.2.5.1) lib/action_dispatch/journey/router.rb:30:in `each'
actionpack (4.2.5.1) lib/action_dispatch/journey/router.rb:30:in `serve'
actionpack (4.2.5.1) lib/action_dispatch/routing/route_set.rb:815:in `call'
rack (1.6.4) lib/rack/etag.rb:24:in `call'
rack (1.6.4) lib/rack/conditionalget.rb:25:in `call'
rack (1.6.4) lib/rack/head.rb:13:in `call'
actionpack (4.2.5.1) lib/action_dispatch/middleware/params_parser.rb:27:in `call'
actionpack (4.2.5.1) lib/action_dispatch/middleware/flash.rb:260:in `call'
rack (1.6.4) lib/rack/session/abstract/id.rb:225:in `context'
rack (1.6.4) lib/rack/session/abstract/id.rb:220:in `call'
actionpack (4.2.5.1) lib/action_dispatch/middleware/cookies.rb:560:in `call'
activerecord (4.2.5.1) lib/active_record/query_cache.rb:36:in `call'
activerecord (4.2.5.1) lib/active_record/connection_adapters/abstract/connection_pool.rb:653:in `call'
activerecord (4.2.5.1) lib/active_record/migration.rb:377:in `call'
actionpack (4.2.5.1) lib/action_dispatch/middleware/callbacks.rb:29:in `block in call'
activesupport (4.2.5.1) lib/active_support/callbacks.rb:88:in `__run_callbacks__'
activesupport (4.2.5.1) lib/active_support/callbacks.rb:778:in `_run_call_callbacks'
activesupport (4.2.5.1) lib/active_support/callbacks.rb:81:in `run_callbacks'
actionpack (4.2.5.1) lib/action_dispatch/middleware/callbacks.rb:27:in `call'
actionpack (4.2.5.1) lib/action_dispatch/middleware/reloader.rb:73:in `call'
actionpack (4.2.5.1) lib/action_dispatch/middleware/remote_ip.rb:78:in `call'
actionpack (4.2.5.1) lib/action_dispatch/middleware/debug_exceptions.rb:17:in `call'
web-console (2.3.0) lib/web_console/middleware.rb:28:in `block in call'
web-console (2.3.0) lib/web_console/middleware.rb:18:in `catch'
web-console (2.3.0) lib/web_console/middleware.rb:18:in `call'
actionpack (4.2.5.1) lib/action_dispatch/middleware/show_exceptions.rb:30:in `call'
railties (4.2.5.1) lib/rails/rack/logger.rb:38:in `call_app'
railties (4.2.5.1) lib/rails/rack/logger.rb:20:in `block in call'
activesupport (4.2.5.1) lib/active_support/tagged_logging.rb:68:in `block in tagged'
activesupport (4.2.5.1) lib/active_support/tagged_logging.rb:26:in `tagged'
activesupport (4.2.5.1) lib/active_support/tagged_logging.rb:68:in `tagged'
railties (4.2.5.1) lib/rails/rack/logger.rb:20:in `call'
actionpack (4.2.5.1) lib/action_dispatch/middleware/request_id.rb:21:in `call'
rack (1.6.4) lib/rack/methodoverride.rb:22:in `call'
rack (1.6.4) lib/rack/runtime.rb:18:in `call'
activesupport (4.2.5.1) lib/active_support/cache/strategy/local_cache_middleware.rb:28:in `call'
rack (1.6.4) lib/rack/lock.rb:17:in `call'
actionpack (4.2.5.1) lib/action_dispatch/middleware/static.rb:116:in `call'
rack (1.6.4) lib/rack/sendfile.rb:113:in `call'
railties (4.2.5.1) lib/rails/engine.rb:518:in `call'
railties (4.2.5.1) lib/rails/application.rb:165:in `call'
rack (1.6.4) lib/rack/lock.rb:17:in `call'
rack (1.6.4) lib/rack/content_length.rb:15:in `call'
rack (1.6.4) lib/rack/handler/webrick.rb:88:in `service'
/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/webrick/httpserver.rb:138:in `service'
/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/webrick/httpserver.rb:94:in `run'
/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/webrick/server.rb:295:in `block in start_thread'