Authentication in redmine through Facebook, Twitter, Github similar to existing OpenID Authentication.
Download the plugin to your application/root/folder/plugins directory. Be sure to maintain the correct folder name, ‘redmine_tweetbook’.
Configure your keys in config/settings.yml
Run ‘rake redmine:plugins:migrate RAILS_ENV=production’
Restart your redmine as appropriate (e.g., ‘rails s -e production’)
Tested on redmine version 2.1.4