My aim was to have compleatly free development ecosystem for one project. Since this is java project I whanted to have java ecosystem. As a source control system was choosen git and that's why project was hosted at github (you know where it is so I don't put link here).
I start looking for free CI service. First I found Travis-CI but to maintain build there I have to make additional file in my repository (but at that time I was a bit lazy to do so). Fortunally I found another service. It's BuildHive from Cloudbees (and here is the link https://buildhive.cloudbees.com/). This service is based on Jenkins-CI and it was first plus. The second plus was the way to configure build. Actually you don't need to configure build, just type shell comands to build project ant that's it. 