heroku run rails db:migrateできない

表題の通り、heroku run rails db:migrateにてエラーが出て詰まっております。

■エラー内容
bash: rails: command not found

■スペック
・mac os
・Rails 6.0.3.4
・ruby 2.6.6p146 (2020-03-31 revision 67876) [x86_64-darwin19]

下記記事を参考にherokuの設定をしたのですがエラーが出てしまいます。
https://qiita.com/kazukimatsumoto/items/a0daa7281a3948701c39

何卒、お願いいたします。

gemfile
1source 'https://rubygems.org'
2git_source(:github) { |repo| "https://github.com/#{repo}.git" }
3
4ruby '2.6.6'
5
6gem 'rails', '~> 6.0.3', '>= 6.0.3.3'
7gem 'bcrypt'
8gem 'puma',       '~> 4.1'
9gem 'sass-rails', '>= 6'
10gem 'webpacker',  '~> 4.0'
11gem 'turbolinks', '~> 5'
12gem 'jbuilder',   '~> 2.7'
13gem 'bootsnap',    '>= 1.4.2', require: false
14gem 'bootstrap-sass'
15gem 'devise'
16gem 'faker'
17gem 'jquery-rails'
18gem 'will_paginate'
19gem 'bootstrap-will_paginate'
20gem 'carrierwave'
21gem "mini_magick"
22gem 'pry-rails'
23
24group :development, :test do
25  gem "factory_bot_rails"
26  gem 'rubocop-airbnb'
27  gem 'rails-controller-testing'
28  gem 'rspec-rails'
29  gem 'sqlite3'
30  gem 'byebug', platforms: [:mri, :mingw, :x64_mingw]
31end
32
33group :development do
34  gem 'spring-commands-rspec'
35  gem 'web-console', '>= 3.3.0'
36  gem 'listen', '~> 3.2'
37  gem 'spring'
38  gem 'spring-watcher-listen', '~> 2.0.0'
39end
40
41group :test do
42  gem 'webdrivers'
43  gem 'capybara', '>= 2.15'
44  gem 'selenium-webdriver'
45end
46
47group :production do
48  gem 'pg'
49  gem 'fog'
50end
51
52gem 'tzinfo-data'

database.yml
1default: &default
2  adapter: sqlite3
3  pool: <%= ENV.fetch("RAILS_MAX_THREADS") { 5 } %>
4  timeout: 10000
5
6development:
7  <<: *default
8  database: db/development.sqlite3
9
10test:
11  <<: *default
12  database: db/test.sqlite3
13
14production:
15  <<: *default
16  adapter: postgresql
17  encoding: unicode
18  pool: 5