I'll use Travis CI as it's free for open-source projects and easy to get started. Signup and sync your repository & activate CI in your desired repo.
You need a
.travis.yml file to integrate Travis CI for your application. File bellow is an example file to run test & builds for a cordova or phonegap android application :
Using npm and
package.json script section makes your build & test commands more generic.
If you push you changes and travis will continuously test and build your app.
Leave a comment if you have question. Let me know if you want to learn more related topic like auto deploy, building for iOS, integrating with strider or jenkins from me :)