Phabricator

Phabricator is a set of tools that available in open source for developing software in Linux systems.Phabricator is a LAMP application that allows the users to manage the tasks and review code or designs. It intergrates with Git, Mercurial and Subversion. Phabricator was originally developed as an internal tool for Facebook. It is a collaborative platform open to all Wikimedia and Mediawiki.  Phabricator is written in php language and available under Apache 2.0 open source license for MacOSX and Linux, and also supports any platform. Most of the popular companies like Facebook, Dropbox, Groupon develop their web applications using Phabricator.