thoughtbot/clearance — pull request #368 by JoelQ (2013-10-18 17:17:21+00:00)
Title: Allow sign up to be disabled via configuration

There are many instances where you don't want users to be able to sign
up (e.g. admin-only system). Clearance can now disable sign up by
setting:

Clearance.configure do |config|
# other configuration options
config.sign_up = false
end

in `config/initializers/clearance.rb`.