Continuous Integration (CI), is a development practice requiring developers to integrate code into a shared repository multiple times a day. Each and every check-in is then verified by an automated build which allows teams to detect problems early. This practice of integrating regularly helps detects errors quickly, and locate them easily.
In Xcode, you ensure that you are continuously automating and streamlining the building, analyzing, testing, and archiving of your Mac and iOS apps, in order to ensure that they are always in a releasable state.