rails s が起動するまで遅いです…

前提・実現したいこと

rails s でサーバーを立ち上げたいのですが，立ち上がるまで20秒ほどかかってしまいます．
gemfileは以下の通りです．何が原因と思われますか？

該当のソースコード

source 'https://rubygems.org'
git_source(:github) { |repo| "https://github.com/#{repo}.git" }

ruby '2.3.7'

Bundle edge Rails instead: gem 'rails', github: 'rails/rails'
gem 'rails', '> 5.2.2', '>= 5.2.2.1'
Use sqlite3 as the database for Active Record
gem 'sqlite3'
Use Puma as the app server
gem 'puma', '> 3.11'
Use SCSS for stylesheets
gem 'sass-rails', '~> 5.0'
Use Uglifier as compressor for JavaScript assets
gem 'uglifier', '>= 1.3.0'
See https://github.com/rails/execjs#readme for more supported runtimes
gem 'mini_racer', platforms: :ruby

Use CoffeeScript for .coffee assets and views
gem 'coffee-rails', '> 4.2'
Turbolinks makes navigating your web application faster. Read more: https://github.com/turbolinks/turbolinks
gem 'turbolinks', '> 5'
Build JSON APIs with ease. Read more: https://github.com/rails/jbuilder
gem 'jbuilder', '> 2.5'
Use Redis adapter to run Action Cable in production
gem 'redis', '> 4.0'
Use ActiveModel has_secure_password
gem 'bcrypt', '~> 3.1.7'

Use ActiveStorage variant
gem 'mini_magick', '~> 4.8'

Use Capistrano for deployment
gem 'capistrano-rails', group: :development

Reduces boot times through caching; required in config/boot.rb
gem 'bootsnap', '>= 1.1.0', require: false

group :development, :test do
Call 'byebug' anywhere in the code to stop execution and get a debugger console
gem 'byebug', platforms: [:mri, :mingw, :x64_mingw]
end

group :development do
Access an interactive console on exception pages or by calling 'console' anywhere in the code.
gem 'web-console', '>= 3.3.0'
gem 'listen', '>= 3.0.5', '< 3.2'
Spring speeds up development by keeping your application running in the background. Read more: https://github.com/rails/spring
gem 'spring'
gem 'spring-watcher-listen', '~> 2.0.0'
end

group :test do
Adds support for Capybara system testing and selenium driver
gem 'capybara', '>= 2.15'
gem 'selenium-webdriver'
Easy installation and use of chromedriver to run system tests with Chrome
gem 'chromedriver-helper'
end

Windows does not include zoneinfo files, so bundle the tzinfo-data gem
gem 'tzinfo-data', platforms: [:mingw, :mswin, :x64_mingw, :jruby]

該当のソースコード（コマンド）

rails s
=> Booting Puma
=> Rails 5.2.3 application starting in development
=> Run rails server -h for more startup options
Puma starting in single mode...

Version 3.12.1 (ruby 2.3.7-p456), codename: Llamas in Pajamas
Min threads: 5, max threads: 5
Environment: development
Listening on tcp://localhost:3000

Use Ctrl-C to stop