Varslist is a ruby gem that helps to identify the env variables that are being used in your project.

In your rails project by default the the environment variables that are missing are shown when starting the server

Add this line to your application's Gemfile:

  gem 'varslist'

And then execute:

  bundle install

Or install it yourself as:

  gem install varslist

To generate the configuration initializer file, run:

  rails generate varslist:install

This will create a config/initializers/varslist.rb file where you can customize the gem settings.