Travis CI - Focus on writing code. Let Travis CI take care of running your tests and deploying your apps.
CircleCI - CircleCI gives web developers powerful Continuous Integration and Deployment with easy setup and maintenance.
Jenkins - Jenkins is an open-source continuous integration server with 300+ plugins to support all kinds of software development
10words.io - Discover new apps and startups in 10 words or less
Chef - Automation for all of your technology. Overcome the complexity and rapidly ship your infrastructure and apps anywhere with automation.
Heroku CI - Continuous Integration from Heroku