will_paginate undefined method `total_pages' for #<ActiveRecord::Relation

Question

undefined method `total_pages' for #<ActiveRecord::Relation [#<Post id: 9, title: "Testing", created_at: "2022-03-13 06:23:49.233178000 +0000", updated_at: "2022-03-13 06:23:49.531991000 +0000", description: "Yes">]> Getting error in pagination, if I add the pagination the search doesnt work, to make the search work pagination should be removed. Can someone help me solve this please.

posts_controller.rb

class PostsController < ApplicationController
  before_action :set_post, only: %i[ show edit update destroy ]
  

  # GET /posts or /posts.json
  def index
    @posts = Post.paginate(:per_page => 5, :page => params[:page])
  end

  def search
    @posts = Post.search(params[:keyword])
    @keyword = params[:keyword]
    render "index"
  end

private
    # Use callbacks to share common setup or constraints between actions.
    def set_post
      @post = Post.find(params[:id])
    end

    # Only allow a list of trusted parameters through.
    def post_params
      params.require(:post).permit(:title, :content, :description)
    end
end

post.rb file

class Post < ApplicationRecord
    has_rich_text :content
    validates :content, length: { minimum: 10 }
    validates :title, presence: true
  

    def self.search(keyword)
        where(["title like? ", "%#{keyword}%"])
    end
end

index.html.erb file

<p style="color: green"><%= notice %></p>

<div class="search-form">
  <%= form_with url: search_path, method: :get, local: true do |f| %>
    <%= f.text_field :keyword, value: @keyword %>
    <%= f.submit "Search" %>
  <% end %>
</div>
      
<h1>Titles</h1>

<div id="posts">
  <% @posts.each do |post| %>
    <%= render post %>
    <p>
      <%= link_to "Show", post %><br>
      <%= "Created at:" %><%= time_ago_in_words(post.created_at) %><%= " ago" %><br>
      <%= time_ago_in_words(post.updated_at) %><%= " ago" %>

    </p>
  <% end %>
<%= will_paginate @posts %>
</div>

I am expecting for both search and pagination to work. When I search a title it should render all the titles from all the pages.