Somehow `test_config_another_database` didn't fail on CI, but it will
fail locally.

https://travis-ci.org/rails/rails/jobs/356212950#L2474-L2482

```
% bundle exec ruby -w -Itest test/generators/app_generator_test.rb -n test_config_another_database
Run options: -n test_config_another_database --seed 7260

# Running:

F

Failure:
AppGeneratorTest#test_config_another_database [test/generators/app_generator_test.rb:417]:
Expected /^\s*gem\s+["']mysql2["'], '~> 0.4.4'$*/ to match "source 'https://rubygems.org'\ngit_source(:github) { |repo| \"https://github.com/\#{repo}.git\" }\n\nruby '2.5.0'\n\n# Bundle edge Rails instead: gem 'rails', github: 'rails/rails'\ngem 'rails', '~> 6.0.0.alpha'\n# Use mysql as the database for Active Record\ngem 'mysql2', '>= 0.4.4', '< 0.6.0'\n# Use Puma as the app server\ngem 'puma', '~> 3.11'\n# Use SCSS for stylesheets\ngem 'sass-rails', '~> 5.0'\n# Use Uglifier as compressor for JavaScript assets\ngem 'uglifier', '>= 1.3.0'\n# See https://github.com/rails/execjs#readme for more supported runtimes\n# gem 'mini_racer', platforms: :ruby\n\n# Use CoffeeScript for .coffee assets and views\ngem 'coffee-rails', '~> 4.2'\n# Turbolinks makes navigating your web application faster. Read more: https://github.com/turbolinks/turbolinks\ngem 'turbolinks', '~> 5'\n# Build JSON APIs with ease. Read more: https://github.com/rails/jbuilder\ngem 'jbuilder', '~> 2.5'\n# Use Redis adapter to run Action Cable in production\n# gem 'redis', '~> 4.0'\n# Use ActiveModel has_secure_password\n# gem 'bcrypt', '~> 3.1.7'\n\n# Use ActiveStorage variant\n# gem 'mini_magick', '~> 4.8'\n\n# Use Capistrano for deployment\n# gem 'capistrano-rails', group: :development\n\n# Reduces boot times through caching; required in config/boot.rb\ngem 'bootsnap', '>= 1.1.0', require: false\n\ngroup :development, :test do\n  # Call 'byebug' anywhere in the code to stop execution and get a debugger console\n  gem 'byebug', platforms: [:mri, :mingw, :x64_mingw]\nend\n\ngroup :development do\n  # Access an interactive console on exception pages or by calling 'console' anywhere in the code.\n  gem 'web-console', '>= 3.3.0'\n  gem 'listen', '>= 3.0.5', '< 3.2'\n  # Spring speeds up development by keeping your application running in the background. Read more: https://github.com/rails/spring\n  gem 'spring'\n  gem 'spring-watcher-listen', '~> 2.0.0'\nend\n\ngroup :test do\n  # Adds support for Capybara system testing and selenium driver\n  gem 'capybara', '>= 2.15', '< 4.0'\n  gem 'selenium-webdriver'\n  # Easy installation and use of chromedriver to run system tests with Chrome\n  gem 'chromedriver-helper'\nend\n\n# Windows does not include zoneinfo files, so bundle the tzinfo-data gem\ngem 'tzinfo-data', platforms: [:mingw, :mswin, :x64_mingw, :jruby]\n".

bin/rails test test/generators/app_generator_test.rb:411

Finished in 0.174681s, 5.7247 runs/s, 34.3483 assertions/s.
1 runs, 6 assertions, 1 failures, 0 errors, 0 skips
```

With the disabling of TLS 1.0 by most major websites, continuing to run
IE8 or lower becomes increasingly difficult so default to not enforcing
UTF-8 encoding as it's not relevant to other browsers.

Add `//= require rails-ujs`

Closes #32094

- Do not generate `javascript_include_tag` if `--skip-javascript`
- Generate `<%= csp_meta_tag %>`. Related to #32018.

Since #30241, if namepsace is specified, routes will be generated even
if there is no actions.

However, it seems that this behavior is not intentionally added behavior.
As with 5.1, routes should not be generated if actions are not specified.

Fixes #32072.

Remove redundant assertions of an absence of `mini_magick` in `Gemfile`
since `bin/rails app:update` does not update Gemfile.
This assertions was added by 4a835aa3,
after reviewing of https://github.com/rails/rails/pull/32049 i realized
that assertions are redundant.

The purpose of keeping app/views folder in API apps is that it's used for
mailer views so doesn't makes sense to keep it when Action Mailer is skipped.

Some places we can't remove because Ruby still don't have a method
equivalent to strip_heredoc to be called in an already existent string.

See https://github.com/rails/rails/pull/31957#issuecomment-364817423

The purpose of `--force` is not to have any prompt whether a file should
be kept or overwritten. In general, all existing files should be overwritten.
However, `config/master.key` is special because it is git-ignored, and
overwriting it will cause the app not to run (since there won't be a way
to decrypt the credentials).

As a result, it's probably better to keep the existing config/master.key.

Incompatible settings are included in the settings set by `load_defaults`.
So, I think that target version should be updated by a user when becomes
available, and should not be updated with `app:update`.

This is similar to #30700 which ensures the `--quiet` option of `rails new`
is respected by the `MasterKeyGenerator` (missing from #30067).

Before this commit, running `rails new app --force` would still prompt the
user what to do with the conflict in `config/master.key`:

```
              …
   identical  config/locales/en.yml
    conflict  config/master.key
Overwrite /Users/claudiob/Desktop/pizza/config/master.key? (enter "h" for help) [Ynaqdh]
```

After this commit, `config/master.key` is overwritten:

```
           …
identical  config/locales/en.yml
    force  config/master.key
   append  .gitignore
```

The newly added test generates an app and then generates it again with
`--force`. Without this commit, the test would just wait forever for user
input.

pg-1.0.0 is just released and most Gemfiles don't restrict
it's version. But the version is checked when connecting to
the database, which leads to the following error:

Gem::LoadError: can't activate pg (~> 0.18), already activated pg-1.0.0

See also this pg issue:
https://bitbucket.org/ged/ruby-pg/issues/270/pg-100-x64-mingw32-rails-server-not-start

Preparation for pg-1.0 was done in commit f28a3310,
but the pg version constraint was not yet relaxed.

  Remove `AppGeneratorTest#test_active_storage_install`.
  The test is added by 67db41aa,
  since #31534 this test doesn't test anything.

  Remove redundant assertions in `SharedGeneratorTests`.
  These assertions is added by 4a835aa3.
  Follows 67db41aa, #31534.

`invoke_all` cause `bundle install`. This will install gems actually
defined in `Gemfile`. To avoid this, stubbed `bundle_command`.

Fixes #31557

`skip_bundle` option was removed from plugin generator in 9b72fcc3.

Specifying the `--dev` option is when want to change the codebase,
as it is not necessary to cache it.

Context: https://github.com/rails/rails/pull/31485#issuecomment-352452653

`bootsnap` is a useful gem normally. However, `bootsnap` is unnecessary
when generating a Rails application to be used only for testing.
So I want to control whether use this or not by option.

See #31315 for full discussion

We probably don't have any tests for the `--webpack` option.
related: #27288

With the current code, a failing test shows this error, which is missing
the number of times called and has two periods at the end.

```
/railties$ be ruby -Itest test/generators/app_generator_test.rb -n test_active_storage_install

Failure:
AppGeneratorTest#test_active_storage_install [test/generators/app_generator_test.rb:313]:
active_storage:install expected to be called once, but was called  times..
Expected: 1
  Actual: 2
```

After the fix, the error message looks correct:

```
/railties$ be ruby -Itest test/generators/app_generator_test.rb -n test_active_storage_install

Failure:
AppGeneratorTest#test_active_storage_install [test/generators/app_generator_test.rb:313]:
active_storage:install expected to be called once, but was called 2 times.
Expected: 1
  Actual: 2
```

Follow up of 924a368f

Since `ContentSecurityPolicy::Middleware` is not loaded in API-only
Applications, initializer is unnecessary.
Ref: https://github.com/rails/rails/blob/9c10fec4c06da38f8975dfb851f4d899aa85f8b7/railties/lib/rails/application/default_middleware_stack.rb#L66..L68

- Followup of #31162

In order to use early hints, need to use Puma 3.11.0 or higher.
So, I think that should specify that version in newly generated applications.

Ref: https://github.com/puma/puma/commit/f6f3892f4d82638fb7a2a57d993641b1486ee88a

This was added with 27f103fc for link labels and fields.
However, `form_with` changed to generates ids by default with d3893ec3.
So I think that adding an explicit ids is unnecessary.

Since fbd1e98c, Rails plugin does not
run `bundle install` when generating.
Therefore, `after_bundle` callback is not actually executed after `bundle`.

Since there is a difference between the name and the actual behavior,
I think that should be remove.

We generate master key on `rails new`.
Therefore, if do not add master key to `.gitginore` on `rails new`as
well, there is a possibility that the master key will be committed
accidentally.

Ensure plugin_generator adds to new line in Gemfile, even if the Gemfile
does not end with an empty line.

[Lisa Ugray, Nikita Penzin]

Make clear that the files are not to be run for interpreters.

Fixes #23847.
Fixes #30690.
Closes #23878.

Allow edits of existing encrypted secrets generated on Rails 5.1,
but refer to credentials when attempting to setup.

This also removes the need for any of the setup code, so the
generator can be ripped out altogether.

These were added in #30101, after #31084 it became redundant.

In order to execute the `rails` command, need to run bundle install in
advance.
Therefore, if skipped bundle install, `rails` command may fail and
should not do it.

Omit `rails activestorage:install` for jdbcmysql, jdbc and shebang tests

AppGeneratorTest#test_config_jdbcmysql_database

  rails aborted!
  LoadError: Could not load 'active_record/connection_adapters/mysql_adapter'.
  Make sure that the adapter in config/database.yml is valid.
  If you use an adapter other than 'mysql2', 'postgresql' or 'sqlite3' add
  the necessary adapter gem to the Gemfile.
  (compressed)
  bin/rails:4:in `<main>'
  Tasks: TOP => activestorage:install => environment
  (See full trace by running task with --trace)

AppGeneratorTest#test_config_jdbc_database

  rails aborted!
  LoadError: Could not load 'active_record/connection_adapters/jdbc_adapter'.
  Make sure that the adapter in config/database.yml is valid.
  If you use an adapter other than 'mysql2', 'postgresql' or 'sqlite3' add
  the necessary adapter gem to the Gemfile.
  (compressed)
  bin/rails:4:in `<main>'
  Tasks: TOP => activestorage:install => environment
  (See full trace by running task with --trace)

AppGeneratorTest#test_shebang_is_added_to_rails_file

  /home/ubuntu/.rbenv/versions/2.4.1/bin/ruby: no Ruby script found in input (LoadError)

Prevent PendingMigrationError in tests

 * Run `bin/rails db:migrate RAILS_ENV=test` in test_cases before start tests to prevent PendingMigrationError
 * FileUtils.rm_r("db/migrate")
 * --skip-active-storage

Fix failed tests in `railties/test/railties/engine_test.rb`

Related to #30111

Imporve `SharedGeneratorTests#test_default_frameworks_are_required_when_others_are_removed`

 - Explicitly skip active_storage
 - Ensure that skipped frameworks are commented
 - Ensure that default frameworks are not commented

Fix error `Errno::ENOSPC: No space left on device - sendfile`

Since `rails new` runs `rails active_storage:install`
that boots an app.

Since adding Bootsnap 0312a5c6
during booting an app, it creates the cache:

   264K    tmp/cache/bootsnap-load-path-cache
   27M     tmp/cache/bootsnap-compile-cache

* teardown_app must remove app