Railsプロジェクトのコード中のTODOやFIXMEコメントを一覧で出力する bin/rails notes が便利。

bin/rails notesは、特定のキーワードで始まるコードコメントを検索して表示します。bin/rails notes --helpで利用法を表示できます。

コマンドラインツール - Railsガイド

Usage

$ bin/rails notes --help
Usage:
  bin/rails notes

Options:
  -a, [--annotations=one two three]  # Filter by specific annotations, e.g. Foobar TODO

Show comments in your code annotated with FIXME, OPTIMIZE, and TODO

サンプル出力

$ bin/rails notes
app/controllers/admin/users_controller.rb:
  * [ 20] [TODO] any other way to do this?
  * [132] [FIXME] high priority for next deploy

lib/school.rb:
  * [ 13] [OPTIMIZE] refactor this code to make it faster
  * [ 17] [FIXME]

$ bin/rails notes --annotations FIXME RELEASE
app/controllers/admin/users_controller.rb:
  * [101] [RELEASE] We need to look at this before next release
  * [132] [FIXME] high priority for next deploy

lib/school.rb:
  * [ 17] [FIXME]