Rails 投稿ページを作っているが、常に投稿日がログインした日付になっている。

Ruby on Railsで投稿記事ページを作成しています。
テスト投稿をすると、投稿日が常にログインした日付（今日の日付）になっていまいます。
（４日前に投稿した記事が常にその日の投稿日になります。）

どこの部分が問題かわかりません。（db, View, Config....?)

原因を教えてください。

※追記

(schema.rb)


ActiveRecord::Schema.define(version: 2021_11_05_042913) do

  create_table "book_comments", force: :cascade do |t|
    t.integer "user_id"
    t.integer "book_id"
    t.text "comment"
    t.datetime "created_at", null: false
    t.datetime "updated_at", null: false
  end

  create_table "books", force: :cascade do |t|
    t.string "title"
    t.text "body"
    t.integer "user_id"
    t.datetime "created_at", null: false
    t.datetime "updated_at", null: false
  end

  create_table "favorites", force: :cascade do |t|
    t.integer "user_id"
    t.integer "book_id"
    t.datetime "created_at", null: false
    t.datetime "updated_at", null: false
  end

  create_table "relationships", force: :cascade do |t|
    t.integer "follower_id"
    t.integer "followed_id"
    t.datetime "created_at", null: false
    t.datetime "updated_at", null: false
  end

  create_table "users", force: :cascade do |t|
    t.string "email", default: "", null: false
    t.string "encrypted_password", default: "", null: false
    t.string "reset_password_token"
    t.datetime "reset_password_sent_at"
    t.datetime "remember_created_at"
    t.string "name"
    t.text "introduction"
    t.string "profile_image_id"
    t.datetime "created_at", null: false
    t.datetime "updated_at", null: false
    t.index ["email"], name: "index_users_on_email", unique: true
    t.index ["reset_password_token"], name: "index_users_on_reset_password_token", unique: true
  end

end

(users_controller.rb)

class UsersController < ApplicationController
  before_action :authenticate_user!
  before_action :ensure_correct_user, only: [:edit, :update]

  def show
    @user = User.find(params[:id])
    @books = @user.books
    @book = Book.new
    @today_book =  @books.created_today
    @yesterday_book = @books.created_yesterday
    @this_week_book = @books.created_this_week
    @last_week_book = @books.created_last_week
  end

  def index
    @users = User.all
    @book = Book.new
  end

  def edit
    @user = User.find(params[:id])
  end

  def update
    if @user.update(user_params)
      redirect_to user_path(@user), notice: "You have updated user successfully."
    else
      render "edit"
    end
  end

  private

  def user_params
    params.require(:user).permit(:name, :introduction, :profile_image)
  end

  def ensure_correct_user
    @user = User.find(params[:id])
    unless @user == current_user
      redirect_to user_path(current_user)
    end
  end
end

(books.rb)

class Book < ApplicationRecord
  belongs_to :user
	has_many :favorites, dependent: :destroy
	has_many :book_comments, dependent: :destroy
	has_many :favorited_users, through: :favorites, source: :user #いいね数で順番を変えるための
	
  validates :title, presence: true
  validates :body, presence: true, length: { maximum: 200 }

# 	いいね機能
	def favorited_by?(user)
		favorites.where(user_id: user.id).exists?
	end
	
# 	検索機能
	def self.search_for(content, method)
    if method == 'perfect'
      Book.where(title: content)
    elsif method == 'forward'
      Book.where('title LIKE ?', content+'%')
    elsif method == 'backward'
      Book.where('title LIKE ?', '%'+content)
    else
      Book.where('title LIKE ?', '%'+content+'%')
    end
  end
  
  # 投稿日数を表示させる
  scope :created_today, -> { where(created_at: Time.zone.now.all_day) } 
  scope :created_yesterday, -> { where(created_at: 1.day.ago.all_day) } 
  scope :created_this_week, -> { where(created_at: 6.day.ago.beginning_of_day..Time.zone.now.end_of_day) } 
  scope :created_last_week, -> { where(created_at: 2.week.ago.beginning_of_day..1.week.ago.end_of_day) }
  
end


(_book_index.html.erb)


<table class='table table-hover table-inverse'>
  <thead>
    <tr>
      <th></th>
      <th>Title</th>
      <th>Opinion</th>
      <th colspan="3"></th>
    </tr>
  </thead>
  <tbody>
    <% books.each do |book| %>
      <tr id="book_<%= book.id %>">
        <td><%= link_to user_path(book.user) do %>
          <%= attachment_image_tag(book.user, :profile_image, :fill, 50, 50, fallback: "no-image-icon.jpg") %>
          <% end %>
        </td>
        <td><%= link_to book.title, book_path(book), class: "book_#{book.id}" %></td>
        <td><%= book.body %></td>
        <td class="favorite-btn"><%= render "favorites/favorite-btn", book: book %></td>
        <td class="comments-count">コメント数: <%= book.book_comments.count %></td>
      </tr>
    <% end %>
  </tbody>
</table>
<h3>投稿数の前日比・前週比</h3>
  <div class="table_width">
    <table class='table table-bordered'>
      <thead>
        <tr> 
          <th>今日の投稿数</th>
          <th>前日の投稿数</th>
          <th>前日比</th>
        </tr>
      </thead>
      <tbody>
        <tr>
          <td><%=  @today_book.count %></td>
          <td><%= @yesterday_book.count %></td>
          <td>
            <% if @yesterday_book.count == 0 %>
              前日の投稿が0のため計算できません
            <% else %>
              <% @the_day_before =   @today_book.count / @yesterday_book.count.to_f  %>
              <%= (@the_day_before * 100).round %>%
            <% end %>
          </td>
        </tr>
      </tbody>
    </table>
  </div>
  <div class="table_width">
    <table class='table table-bordered'>
      <thead>
        <tr> 
          <th>今週の投稿数</th>
          <th>前週の投稿数</th>
          <th>前週比</th>
        </tr>
      </thead>
      <tbody>
        <tr>
          <td><%= @this_week_book.count %></td>
          <td><%= @last_week_book.count %></td>
          <td>
            <% if @last_week_book.count == 0 %>
              前週の投稿が0のため計算できません
            <% else %>
              <% @the_week_before = @this_week_book.count / @last_week_book.count.to_f  %>
              <%= (@the_week_before * 100).round %>%
            <% end %>
          </td>
        </tr>
      </tbody>
    </table>
  </div>

(show.html.erb)

<div class='container px-5 px-sm-0'>
  <div class='row'>
    <div class='col-md-3'>
      <h2>User info</h2>
      <%= render 'info', user: @user %>
      <h2 class="mt-3">New book</h2>
      <%= render 'books/form', book: @book %>
    </div>
    <div class='col-md-8 offset-md-1'>
      <h2>Books</h2>
      <%= render 'book_index',books: @books %>
      <!--%= current_user.books.where('created_at > ?', Date.today).count %>-->
      <!--↑↑詳細ページに本日の投稿数を表示-->
    </div>
  </div>
</div>