Recommendation of CI Tools for JavaScript package

My company is building a javascript library that works very much like a google analytics javascript package: Our customers are adding a tag. The javascript code is ruing against our servers - parallel to the normal users' flow.

I would like to build an automation framework for testing the product - but I have difficulty deciding which CI tool is best for this use case?

Our local build script is written in gulp, and our code is on a git server.

The Build and Test should be able to run the gulp, deploy a file, configure a DB, run SauceLabs, and examine some results from a server.

What CI tools are best suitable for the task?