rails root画面がうまく設定できない

root to: "tasks#index"

config\roots
Rails.application.routes.draw do

  root to: "tasks#index"

  get 'login', to: 'sessions#new'
  post 'login', to: 'sessions#create'
  delete 'logout', to: 'sessions#destroy'

  get 'signup', to: 'users#new'

  resources :tasks

  resources :users, only: [:index, :show, :new, :create]
end

taks_controller


class TasksController < ApplicationController

    before_action :require_user_logged_in
    before_action :correct_user, only: [:destroy]


    def index
       @tasks = Task.all#.page(params[:page]).per(3)

    if logged_in?
      @task = current_user.tasks.build  # form_with 用
      @tasks = current_user.tasks.order(id: :desc).page(params[:page])
    end

    end

    def show
        @task = Task.find(params[:id])
    end

    def new
       @task = Task.new
    end
 .......
.......

sessins_controller

class SessionsController < ApplicationController
  def new
  end

  def create
    email = params[:session][:email].downcase
    password = params[:session][:password]
    if login(email, password)
      flash[:success] = 'ログインに成功しました。'
      redirect_to root_url
    else
      flash.now[:danger] = 'ログインに失敗しました。'
      render :new
    end
  end

  def destroy
     session[:user_id] = nil
    flash[:success] = 'ログアウトしました。'
    redirect_to root_url
  end

  private

  def login(email, password)
    @user = User.find_by(email: email)
    if @user && @user.authenticate(password)
      # ログイン成功
      session[:user_id] = @user.id
      return true
    else
      # ログイン失敗
      return false
    end
  end
end

sessions\new.html.erb

<h3>sessions#new</h3>

<div class="text-center">
  <h1>Log in</h1>
</div>

<div class="row">
  <div class="col-sm-6 offset-sm-3">

    <%= form_with(url: login_path, scope: :session, local: true) do |f| %>

      <div class="form-group">
        <%= f.label :email, 'Email' %>
        <%= f.email_field :email, class: 'form-control' %>
      </div>

      <div class="form-group">
        <%= f.label :password, 'Password' %>
        <%= f.password_field :password, class: 'form-control' %>
      </div>

      <%= f.submit 'Log in', class: 'btn btn-primary btn-block' %>
    <% end %>

    <p>New user? <%= link_to 'Sign up now!', signup_path %></p>
  </div>
</div>