Decent Authentication is a sample application that implements authentication in Rails without the use of a third-party generator or engine. You might often hear the advice that you should not "Roll your own authentication" but that doesn't mean you have to use a gem.
Features:
Secure defaults:
Run the setup script, start the server, then click 'Create Account' from the sign in screen.
# install gems, create database.yml config, and setup the database
./bin/setup
# run the test suite
./bin/rake
# run the test suite as well as brakeman, simplecov, rails_best_practices, and rubocop
./bin/rake analyze