rails consoleでLibrary not loaded: /usr/local/opt/readline/lib/libreadline.7.dylib (LoadError)ってエラーが出る件について

まずエラー載せますね。
参考になるかもしれないのでエラーログまるごと。

```sh
YourName@YourName application_name % bundle exec rails c
Traceback (most recent call last):
	42: from bin/rails:4:in `<main>'
	41: from /Users/YourName/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/activesupport-6.0.2.1/lib/active_support/dependencies.rb:325:in `require'
	40: from /Users/YourName/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/activesupport-6.0.2.1/lib/active_support/dependencies.rb:291:in `load_dependency'
	39: from /Users/YourName/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/activesupport-6.0.2.1/lib/active_support/dependencies.rb:325:in `block in require'
	38: from /Users/YourName/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/bootsnap-1.4.5/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:30:in `require'
	37: from /Users/YourName/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/bootsnap-1.4.5/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:21:in `require_with_bootsnap_lfi'
	36: from /Users/YourName/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/bootsnap-1.4.5/lib/bootsnap/load_path_cache/loaded_features_index.rb:92:in `register'
	35: from /Users/YourName/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/bootsnap-1.4.5/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:22:in `block in require_with_bootsnap_lfi'
	34: from /Users/YourName/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/bootsnap-1.4.5/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:22:in `require'
	33: from /Users/YourName/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/railties-6.0.2.1/lib/rails/commands.rb:18:in `<top (required)>'
	32: from /Users/YourName/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/railties-6.0.2.1/lib/rails/command.rb:44:in `invoke'
	31: from /Users/YourName/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/railties-6.0.2.1/lib/rails/command.rb:70:in `find_by_namespace'
	30: from /Users/YourName/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/railties-6.0.2.1/lib/rails/command/behavior.rb:39:in `lookup'
	29: from /Users/YourName/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/railties-6.0.2.1/lib/rails/command/behavior.rb:39:in `each'
	28: from /Users/YourName/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/railties-6.0.2.1/lib/rails/command/behavior.rb:40:in `block in lookup'
	27: from /Users/YourName/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/railties-6.0.2.1/lib/rails/command/behavior.rb:40:in `each'
	26: from /Users/YourName/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/railties-6.0.2.1/lib/rails/command/behavior.rb:44:in `block (2 levels) in lookup'
	25: from /Users/YourName/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/activesupport-6.0.2.1/lib/active_support/dependencies.rb:325:in `require'
	24: from /Users/YourName/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/activesupport-6.0.2.1/lib/active_support/dependencies.rb:291:in `load_dependency'
	23: from /Users/YourName/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/activesupport-6.0.2.1/lib/active_support/dependencies.rb:325:in `block in require'
	22: from /Users/YourName/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/bootsnap-1.4.5/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:30:in `require'
	21: from /Users/YourName/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/bootsnap-1.4.5/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:21:in `require_with_bootsnap_lfi'
	20: from /Users/YourName/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/bootsnap-1.4.5/lib/bootsnap/load_path_cache/loaded_features_index.rb:92:in `register'
	19: from /Users/YourName/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/bootsnap-1.4.5/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:22:in `block in require_with_bootsnap_lfi'
	18: from /Users/YourName/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/bootsnap-1.4.5/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:22:in `require'
	17: from /Users/YourName/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/railties-6.0.2.1/lib/rails/commands/console/console_command.rb:4:in `<top (required)>'
	16: from /Users/YourName/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/activesupport-6.0.2.1/lib/active_support/dependencies.rb:325:in `require'
	15: from /Users/YourName/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/activesupport-6.0.2.1/lib/active_support/dependencies.rb:291:in `load_dependency'
	14: from /Users/YourName/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/activesupport-6.0.2.1/lib/active_support/dependencies.rb:325:in `block in require'
	13: from /Users/YourName/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/bootsnap-1.4.5/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:30:in `require'
	12: from /Users/YourName/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/bootsnap-1.4.5/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:21:in `require_with_bootsnap_lfi'
	11: from /Users/YourName/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/bootsnap-1.4.5/lib/bootsnap/load_path_cache/loaded_features_index.rb:92:in `register'
	10: from /Users/YourName/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/bootsnap-1.4.5/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:22:in `block in require_with_bootsnap_lfi'
	 9: from /Users/YourName/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/bootsnap-1.4.5/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:22:in `require'
	 8: from /Users/YourName/.rbenv/versions/2.5.1/lib/ruby/2.5.0/irb/completion.rb:10:in `<top (required)>'
	 7: from /Users/YourName/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/activesupport-6.0.2.1/lib/active_support/dependencies.rb:325:in `require'
	 6: from /Users/YourName/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/activesupport-6.0.2.1/lib/active_support/dependencies.rb:291:in `load_dependency'
	 5: from /Users/YourName/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/activesupport-6.0.2.1/lib/active_support/dependencies.rb:325:in `block in require'
	 4: from /Users/YourName/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/bootsnap-1.4.5/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:30:in `require'
	 3: from /Users/YourName/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/bootsnap-1.4.5/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:21:in `require_with_bootsnap_lfi'
	 2: from /Users/YourName/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/bootsnap-1.4.5/lib/bootsnap/load_path_cache/loaded_features_index.rb:92:in `register'
	 1: from /Users/YourName/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/bootsnap-1.4.5/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:22:in `block in require_with_bootsnap_lfi'
/Users/YourName/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/bootsnap-1.4.5/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:22:in `require': dlopen(/Users/YourName/.rbenv/versions/2.5.1/lib/ruby/2.5.0/x86_64-darwin18/readline.bundle, 9): Library not loaded: /usr/local/opt/readline/lib/libreadline.7.dylib (LoadError)
  Referenced from: /Users/YourName/.rbenv/versions/2.5.1/lib/ruby/2.5.0/x86_64-darwin18/readline.bundle
  Reason: image not found - /Users/YourName/.rbenv/versions/2.5.1/lib/ruby/2.5.0/x86_64-darwin18/readline.bundle

```

さて、これの解決方法について調べてみると、

1. /usr/local/opt/readline/lib に以下のファイルを、->のようにシンボリックリンクする
  * libreadline.dylib -> libreadline.dylib
  * libhistory.dylib -> libreadline.dylib

2. ７系のreadlineを入れて、そちらを使用するようにする
3. [rb-readline](https://github.com/ConnorAtherton/rb-readline)を突っ込む

などが見受けられましたが、個人的には**3**が影響範囲小さくて良いなと思い、そちらを選択しました。
本当はもっとちゃんと調べたかったけど、`rails console`を使いたいだけなのに、ここに時間を取られるのもアホらしいなと思ったので雑に解決。

### おわりに
`brew info readline`とかやっても７系のreadline出てこなかったんですが、もうインストールできないのだろうか？