Using Rack::Auth::Basic

basic_authentication.rb

# config/staging.rb
Rails.application.configure do
  config.middleware.use "::Rack::Auth::Basic" do |u, p|
    [u, p] == [ENV["BASIC_AUTH_USERNAME"], ENV["BASIC_AUTH_PASSWORD"]]
  end
end

# .env
BASIC_AUTH_USERNAME = some_value
BASIC_AUTH_PASSWORD = some_password