Redmine is an open source project management and bug/issue tracking system.
First released in 2006, Redmine is an open source project management system influenced by older systems such as trac. Developed in the ruby-on-rails framework, Redmine is a cross platform and cross-database system. It is released under the GPLv2 license.
More information can be found on the official redmine website: http://www.redmine.org