Git: version control system
Jenkins: continuous integration
Jenkinks is an application of continuous integration monitore performing repeated as builds software or automated tasks jobs.
Capistrano: deploying web applications
Capistrano is an open source tool for running scripts on multiple servers, its main use is deploying web applications. It automates the process of deploying a new version of an application on one or more web servers.
Chef: solution to managing and automating large-scale infrastructure
Chef is a powerful solution to managing and automating large-scale infrastructure that includes premium features like multi-tenancy, role-based access control, reporting and support from automation experts at Chef.
Open source Chef is an open-source free version of Chef server that is the basis for both versions of Chef.