railsの投稿時間をローカル時間で表示させたいです

前提・実現したいこと

railsの投稿時間をローカル時間で表示させたいです。

今はpost作成時に投稿時間（created_at）をUTC時間で保存し、<%= @post.created_at %>
で表示させる形にしています（現在はUTCで表示）。
DBにUTCで保存した日時をviewで表示させるときにユーザーのタイムゾーンに変換する方法ってありますか？

Railsでタイムゾーンを扱う方法を現役エンジニアが解説【初心者向け】
Railsにおけるタイムゾーンの注意点
にあるようにRailsでは東京など特定の都市のタイムゾーンに変換して表示させたり、サーバーのタイムゾーンで表示させることはできるようなのですが、各ユーザーのタイムゾーンでの表示の方法が見つかりません。

local_timeというそれっぽいgemを見つけて試したのですが、エラーになってしまいました。
basecamp/local_time

gem 'local_time'　インストール
local-time.js　作成、以下追加
　　import LocalTime from "local-time"
　　LocalTime.start()
application.js　に以下を追加
　　//= require local-time
Show.html.erb　の時間表示部分を変更
　　<%= @post.created_at %>　->
　　<%= local_time(@post.created_at) %>

以下がエラーログになります。

Started GET "/posts/index" for 172.18.0.1 at 2020-09-22 01:04:24 +0000
Cannot render console from 172.18.0.1! Allowed networks: 127.0.0.1, ::1, 127.0.0.0/127.255.255.255
Processing by PostsController#index as HTML
   [1m [36mUser Load (1.2ms) [0m   [1m [34m
  SELECT
    `users`. *
  FROM
    `users`
  WHERE
    `users`.`id` = 10 LIMIT 1 [0m
  ↳ app/controllers/application_controller.rb:6
  Rendering posts/index.html.erb within layouts/application
   [1m [36mPost Load (4.0ms) [0m   [1m [34m
  SELECT
    `posts`. *
  FROM
    `posts`
  ORDER BY
    `posts`.`created_at` DESC [0m
  ↳ app/views/posts/index.html.erb:20
   [1m [36mCACHE User Load (0.2ms) [0m   [1m [34mSELECT  `users`.* FROM `users` WHERE `users`.`id` = 10 LIMIT 1 [0m  [["id", 10], ["LIMIT", 1]]
  ↳ app/views/posts/index.html.erb:23
   [1m [36mCACHE User Load (0.5ms) [0m   [1m [34mSELECT  `users`.* FROM `users` WHERE `users`.`id` = 10 LIMIT 1 [0m  [["id", 10], ["LIMIT", 1]]
  ↳ app/views/posts/index.html.erb:23
   [1m [36mUser Load (1.7ms) [0m   [1m [34m
  SELECT
    `users`. *
  FROM
    `users`
  WHERE
    `users`.`id` = 1 LIMIT 1 [0m
  ↳ app/views/posts/index.html.erb:23
   [1m [36mUser Load (1.8ms) [0m   [1m [34m
  SELECT
    `users`. *
  FROM
    `users`
  WHERE
    `users`.`id` = 2 LIMIT 1 [0m
  ↳ app/views/posts/index.html.erb:23
   [1m [36mCACHE User Load (0.4ms) [0m   [1m [34mSELECT  `users`.* FROM `users` WHERE `users`.`id` = 1 LIMIT 1 [0m  [["id", 1], ["LIMIT", 1]]
  ↳ app/views/posts/index.html.erb:23
  Rendered posts/index.html.erb within layouts/application (108.4ms)
Completed 200 OK in 2193ms (Views: 2115.2ms | ActiveRecord: 9.7ms)


   [1m [35m (3.2ms) [0m   [1m [35m
  SET
NAMES utf8
,@@SESSION.sql_mode = CONCAT( CONCAT( @@sql_mode ,',STRICT_ALL_TABLES' ) ,',NO_AUTO_VALUE_ON_ZERO' )
,@@SESSION.sql_auto_is_null = 0
,@@SESSION.wait_timeout = 2147483 [0m
   [1m [36mPost Load (100.1ms) [0m   [1m [34m
  SELECT
    `posts`. *
  FROM
    `posts` LIMIT 11 [0m
Started GET "/posts/7" for 172.18.0.1 at 2020-09-22 01:11:20 +0000
Cannot render console from 172.18.0.1! Allowed networks: 127.0.0.1, ::1, 127.0.0.0/127.255.255.255
   [1m [35m (1.6ms) [0m   [1m [35m
  SET
NAMES utf8
,@@SESSION.sql_mode = CONCAT( CONCAT( @@sql_mode ,',STRICT_ALL_TABLES' ) ,',NO_AUTO_VALUE_ON_ZERO' )
,@@SESSION.sql_auto_is_null = 0
,@@SESSION.wait_timeout = 2147483 [0m
  ↳ /usr/local/bundle/gems/activerecord-5.2.4.4/lib/active_record/log_subscriber.rb:98
Processing by PostsController#show as HTML
  Parameters: {"id"=>"7"}
   [1m [36mUser Load (3.4ms) [0m   [1m [34m
  SELECT
    `users`. *
  FROM
    `users`
  WHERE
    `users`.`id` = 10 LIMIT 1 [0m
  ↳ app/controllers/application_controller.rb:6
   [1m [36mPost Load (1.5ms) [0m   [1m [34m
  SELECT
    `posts`. *
  FROM
    `posts`
  WHERE
    `posts`.`id` = 7 LIMIT 1 [0m
  ↳ app/controllers/posts_controller.rb:15
   [1m [36mCACHE User Load (0.0ms) [0m   [1m [34mSELECT  `users`.* FROM `users` WHERE `users`.`id` = 10 LIMIT 1 [0m  [["id", 10], ["LIMIT", 1]]
  ↳ app/controllers/posts_controller.rb:16
   [1m [35m (4.0ms) [0m   [1m [34m
  SELECT
    COUNT( * )
  FROM
    `likes`
  WHERE
    `likes`.`post_id` = 7 [0m
  ↳ app/controllers/posts_controller.rb:17
  Rendering posts/show.html.erb within layouts/application
  Rendered posts/show.html.erb within layouts/application (314.5ms)
Completed 500 Internal Server Error in 717ms (ActiveRecord: 8.9ms)


  
ActionView::Template::Error (undefined method `local_time' for #<#<Class:0x00007f4ac5584118>:0x000055c5ae073180>):
    22:       <br/>
    23:       <div class="post-time">
    24:         <%= @post.created_at %>
    25:         <%= local_time(@post.created_at) %>
    26:       </div>
    27:       <% if Like.find_by(user_id: @current_user.id, post_id: @post.id) %>
    28:         <%= link_to("/likes/#{@post.id}/destroy", {method: "post"}) do %>
  
app/views/posts/show.html.erb:25:in `_app_views_posts_show_html_erb__3079554789774239632_47153758291420'

gem local_timeでなくても、投稿時間をローカル時間で表示させる方法がありましたら教えてください。
よろしくお願いします。