Rails 4.2.10でページアクセス時にエラーになる。

前提・実現したいこと

ログレベルを変更後、Railsサーバを再起動したところ、ブラウザからアクセス時に
エラーが表示されます。
Permission関連のエラーが表示されるようなので、権限の設定の問題かとは思うのですが、今までアクセスできていて、急にアクセスできなくなった理由が分からない状態です。

発生している問題・エラーメッセージ

The Phusion Passenger application server tried to start the web application. But the application itself (and not Passenger) encountered an operating system error.

The error reported by the operating system is:

Permission denied @ rb_sysopen - log/development.log (Errno::EACCES)
  /usr/local/rbenv/versions/2.3.7/lib/ruby/2.3.0/logger.rb:703:in `initialize'
  /usr/local/rbenv/versions/2.3.7/lib/ruby/2.3.0/logger.rb:703:in `open'
  /usr/local/rbenv/versions/2.3.7/lib/ruby/2.3.0/logger.rb:703:in `open_logfile'
  /usr/local/rbenv/versions/2.3.7/lib/ruby/2.3.0/logger.rb:695:in `set_dev'
  /usr/local/rbenv/versions/2.3.7/lib/ruby/2.3.0/logger.rb:635:in `initialize'
  /usr/local/rbenv/versions/2.3.7/lib/ruby/2.3.0/logger.rb:353:in `new'
  /usr/local/rbenv/versions/2.3.7/lib/ruby/2.3.0/logger.rb:353:in `initialize'
  /Myapp/config/application.rb:34:in `new'
  /Myapp/config/application.rb:34:in `<class:Application>'
  /Myapp/config/application.rb:10:in `<module:Myapp>'
  /Myapp/config/application.rb:9:in `<top (required)>'
  /Myapp/config/environment.rb:2:in `require'
  /Myapp/config/environment.rb:2:in `<top (required)>'
  config.ru:3:in `require'
  config.ru:3:in `block in <main>'
  /usr/local/rbenv/versions/2.3.7/lib/ruby/gems/2.3.0/gems/rack-1.6.10/lib/rack/builder.rb:55:in `instance_eval'
  /usr/local/rbenv/versions/2.3.7/lib/ruby/gems/2.3.0/gems/rack-1.6.10/lib/rack/builder.rb:55:in `initialize'
  config.ru:1:in `new'
  config.ru:1:in `<main>'
  /usr/local/rbenv/versions/2.3.7/lib/ruby/gems/2.3.0/gems/passenger-5.3.0/src/helper-scripts/rack-preloader.rb:101:in `eval'
  /usr/local/rbenv/versions/2.3.7/lib/ruby/gems/2.3.0/gems/passenger-5.3.0/src/helper-scripts/rack-preloader.rb:101:in `preload_app'
  /usr/local/rbenv/versions/2.3.7/lib/ruby/gems/2.3.0/gems/passenger-5.3.0/src/helper-scripts/rack-preloader.rb:189:in `block in <module:App>'
  /usr/local/rbenv/versions/2.3.7/lib/ruby/gems/2.3.0/gems/passenger-5.3.0/src/ruby_supportlib/phusion_passenger/loader_shared_helpers.rb:380:in `run_block_and_record_step_progress'
  /usr/local/rbenv/versions/2.3.7/lib/ruby/gems/2.3.0/gems/passenger-5.3.0/src/helper-scripts/rack-preloader.rb:188:in `<module:App>'
  /usr/local/rbenv/versions/2.3.7/lib/ruby/gems/2.3.0/gems/passenger-5.3.0/src/helper-scripts/rack-preloader.rb:30:in `<module:PhusionPassenger>'
  /usr/local/rbenv/versions/2.3.7/lib/ruby/gems/2.3.0/gems/passenger-5.3.0/src/helper-scripts/rack-preloader.rb:29:in `<main>'

The stdout/stderr output of the subprocess so far is:

Error: The application encountered the following error: Permission denied @ rb_sysopen - log/development.log (Errno::EACCES)
    /usr/local/rbenv/versions/2.3.7/lib/ruby/2.3.0/logger.rb:703:in `initialize'
    /usr/local/rbenv/versions/2.3.7/lib/ruby/2.3.0/logger.rb:703:in `open'
    /usr/local/rbenv/versions/2.3.7/lib/ruby/2.3.0/logger.rb:703:in `open_logfile'
    /usr/local/rbenv/versions/2.3.7/lib/ruby/2.3.0/logger.rb:695:in `set_dev'
    /usr/local/rbenv/versions/2.3.7/lib/ruby/2.3.0/logger.rb:635:in `initialize'
    /usr/local/rbenv/versions/2.3.7/lib/ruby/2.3.0/logger.rb:353:in `new'
    /usr/local/rbenv/versions/2.3.7/lib/ruby/2.3.0/logger.rb:353:in `initialize'
    /Myapp/config/application.rb:34:in `new'
    /Myapp/config/application.rb:34:in `<class:Application>'
    /Myapp/config/application.rb:10:in `<module:Myapp>'
    /Myapp/config/application.rb:9:in `<top (required)>'
    /Myapp/config/environment.rb:2:in `require'
    /Myapp/config/environment.rb:2:in `<top (required)>'
    config.ru:3:in `require'
    config.ru:3:in `block in <main>'
    /usr/local/rbenv/versions/2.3.7/lib/ruby/gems/2.3.0/gems/rack-1.6.10/lib/rack/builder.rb:55:in `instance_eval'
    /usr/local/rbenv/versions/2.3.7/lib/ruby/gems/2.3.0/gems/rack-1.6.10/lib/rack/builder.rb:55:in `initialize'
    config.ru:1:in `new'
    config.ru:1:in `<main>'
    /usr/local/rbenv/versions/2.3.7/lib/ruby/gems/2.3.0/gems/passenger-5.3.0/src/helper-scripts/rack-preloader.rb:101:in `eval'
    /usr/local/rbenv/versions/2.3.7/lib/ruby/gems/2.3.0/gems/passenger-5.3.0/src/helper-scripts/rack-preloader.rb:101:in `preload_app'
    /usr/local/rbenv/versions/2.3.7/lib/ruby/gems/2.3.0/gems/passenger-5.3.0/src/helper-scripts/rack-preloader.rb:189:in `block in <module:App>'
    /usr/local/rbenv/versions/2.3.7/lib/ruby/gems/2.3.0/gems/passenger-5.3.0/src/ruby_supportlib/phusion_passenger/loader_shared_helpers.rb:380:in `run_block_and_record_step_progress'
    /usr/local/rbenv/versions/2.3.7/lib/ruby/gems/2.3.0/gems/passenger-5.3.0/src/helper-scripts/rack-preloader.rb:188:in `<module:App>'
    /usr/local/rbenv/versions/2.3.7/lib/ruby/gems/2.3.0/gems/passenger-5.3.0/src/helper-scripts/rack-preloader.rb:30:in `<module:PhusionPassenger>'
    /usr/local/rbenv/versions/2.3.7/lib/ruby/gems/2.3.0/gems/passenger-5.3.0/src/helper-scripts/rack-preloader.rb:29:in `<main>'

該当のソースコード

config/application.rb

require File.expand_path('../boot', __FILE__)

require 'rails/all'

# Require the gems listed in Gemfile, including any gems
# you've limited to :test, :development, or :production.
Bundler.require(*Rails.groups)

module Myapp
  class Application < Rails::Application
    # Settings in config/environments/* take precedence over those specified here.
    # Application configuration should go into files in config/initializers
    # -- all .rb files in that directory are automatically loaded.

    # Set Time.zone default to the specified zone and make Active Record auto-convert to this zone.
    # Run "rake -D time" for a list of tasks for finding time zone names. Default is UTC.
    # config.time_zone = 'Central Time (US & Canada)'

    # The default locale is :en and all translations from config/locales/*.rb,yml are auto loaded.
    # config.i18n.load_path += Dir[Rails.root.join('my', 'locales', '*.{rb,yml}').to_s]
    # config.i18n.default_locale = :de

    # Do not swallow errors in after_commit/after_rollback callbacks.
    config.active_record.raise_in_transactional_callbacks = true

# 追記_20180515
    config.generators.template_engine = :slim   

# 追記_20180515
    config.active_record.default_timezone = :local
    config.time_zone = 'Tokyo'

# 追記_20180521
    config.logger = Logger.new('log/development.log')
    config.log_level = :warn

  end