add bootstrap

app/assets/stylesheets/home.scss

-// Place all the styles related to the Home controller here.
-// They will automatically be included in application.css.
-// You can use Sass (SCSS) here: https://sass-lang.com/

app/controllers/application_controller.rb

 class ApplicationController < ActionController::Base
+  
+  def hello
+    render html: "Welcome to VenJob"
+  end
 end

app/controllers/home_controller.rb

-class HomeController < ApplicationController
-  def index
-  end
-end

app/helpers/home_helper.rb

-module HomeHelper
-end

app/views/home/index.html.erb

-<nav class="navbar navbar-expand-lg navbar-light bg-light">
-    <div class="container-fluid">
-        <a class="navbar-brand" href="#">Navbar</a>
-        <button class="navbar-toggler" type="button" data-bs-toggle="collapse" data-bs-target="#navbarSupportedContent" aria-controls="navbarSupportedContent" aria-expanded="false" aria-label="Toggle navigation">
-            <span class="navbar-toggler-icon"></span>
-        </button>
-        <div class="collapse navbar-collapse" id="navbarSupportedContent">
-            <ul class="navbar-nav me-auto mb-2 mb-lg-0">
-                <li class="nav-item">
-                    <a class="nav-link active" aria-current="page" href="#">Home</a>
-                </li>
-                <li class="nav-item">
-                    <a class="nav-link" href="#">Link</a>
-                </li>
-                <li class="nav-item dropdown">
-                    <a class="nav-link dropdown-toggle" href="#" id="navbarDropdown" role="button" data-bs-toggle="dropdown" aria-expanded="false">
-                        Dropdown
-                    </a>
-                    <ul class="dropdown-menu" aria-labelledby="navbarDropdown">
-                        <li><a class="dropdown-item" href="#">Action</a></li>
-                        <li><a class="dropdown-item" href="#">Another action</a></li>
-                        <li>
-                            <hr class="dropdown-divider">
-                        </li>
-                        <li><a class="dropdown-item" href="#">Something else here</a></li>
-                    </ul>
-                </li>
-                <li class="nav-item">
-                    <a class="nav-link disabled" href="#" tabindex="-1" aria-disabled="true">Disabled</a>
-                </li>
-            </ul>
-            <form class="d-flex">
-                <input class="form-control me-2" type="search" placeholder="Search" aria-label="Search">
-                <button class="btn btn-outline-success" type="submit">Search</button>
-            </form>
-        </div>
-    </div>
-</nav>
-
-<h1>Home#index</h1>
-<p>Find me in app/views/home/index.html.erb</p>
-
-<h1 class="name">HA</h1>

config/routes.rb

 Rails.application.routes.draw do
-  root 'home#index'
+  root 'application#hello'
 end

test/controllers/home_controller_test.rb

-require "test_helper"
-
-class HomeControllerTest < ActionDispatch::IntegrationTest
-  test "should get index" do
-    get home_index_url
-    assert_response :success
-  end
-end