【Rails】一括登録フォームの実装

前提・実現したいこと

Railsにて一括登録フォームの実装を試みています。
indexactionからnewactionへ遷移するまでは実装できたのですが、送信後にエラーが起きてしまっており解決策がわからないためご質問させていただきます。

本文下記に添付しておりますサイトを見まねで実装しました。
そのため内容理解が薄いですが、どなたか解決策をご教示いただけますと幸いです。

発生している問題・エラーメッセージ

該当のソースコード

##workoutdiaries_controller

class WorkoutdiariesController < ApplicationController
  
  before_action :move_to_index, except: :index

	
　def new
    @form = Form::WorkoutdiaryCollection.new
  end
  
  def create
    @form = Form::WorkoutdiaryCollection.new(workoutdiary_collection_params)
    if @form.save
      redirect_to workoutdiaries_path
    else
      render :new
    end
    
  end
  

  
  private 
  def move_to_index
    redirect_to action: :index unless user_signed_in?
  end
  
  def workoutdiary_search_params
    params.fetch(:search, {}).permit(:menu, :date_from, :date_to, :workoutdate_id)
  end
  
  def workoutdiary_collection_params
    params
      .require(:form_workoutdiary_collection)
      .permit(workoutdiaries_attributes: Form::Workoutdiary::REGISTRABLE_ATTRIBUTES)
  end
 
end

## models/workoutdiary.rb

class Workoutdiary < ApplicationRecord

# 	validates  :settype, :weight, :reps, presence: true
  
  belongs_to :user
  validates :user_id, presence: true
  
  belongs_to :workoutdate
  validates :workoutdate_id, presence: true
  
  scope :search, -> (search_params) do
    unless search_params.blank?

    workoutdate_id_is(search_params[:workoutdate_id])
      .date_from(search_params[:date_from])
      .date_to(search_params[:date_to])
    else
      Workoutdiary.where(created_at: Date.current.all_day)
    end
  end
  scope :date_from, -> (from) { where('? <= created_at', from) if from.present? }
  scope :date_to, -> (to) { where('created_at <= ?', to) if to.present? }
  scope :workoutdate_id_is, -> (workoutdate_id) { where(workoutdate_id: workoutdate_id) if workoutdate_id.present? }
  
end

## models/form/workoutdiary.rb

class Form::Workoutdiary < Workoutdiary
  REGISTRABLE_ATTRIBUTES = %i(workoutdate_id settype weight reps weightsecond repssecond weightthird repsthird)
  attr_accessor :workoutdate_id
end

## models/base.rb

class Form::Base
  include ActiveModel::Model
  include ActiveModel::Callbacks
  include ActiveModel::Validations
  include ActiveModel::Validations::Callbacks
end

## models/form/workoutdiary_collection.rb

class Form::WorkoutdiaryCollection < Form::Base
  DEFAULT_ITEM_COUNT = 5
  attr_accessor :workoutdiaries

  def initialize(attributes = {})
    super attributes
    self.workoutdiaries = DEFAULT_ITEM_COUNT.times.map { Form::Workoutdiary.new } unless workoutdiaries.present?
  end

  def workoutdiaries_attributes=(attributes)
    self.workoutdiaries = attributes.map do |_, workoutdiary_attributes|
      Form::Workoutdiary.new(workoutdiary_attributes).tap { |v| v.availability = false }
    end
  end

  def valid?
    valid_workoutdiaries = target_workoutdiaries.map(&:valid?).all?
    super && valid_workoutdiaries
  end

  def save
    return false unless valid?
    Workoutdiary.transaction { target_workoutdiaries.each(&:save!) }
    true
  end

  def target_workoutdiaries
    self.workoutdiaries.select { |v| value_to_boolean(v.register) }
  end
end