Continuous integration using Visual Studio Online and a Bitbucket repository is not a straightforward task, it's not hard but definitely not straightforward.
Continuous integration is the practice to build your code everytime any member of your dev team integrates code changes to the main repository.
Integrate Visual Studio Online with Bitbucket requires a couple of thing:
- You need to create a web app (aka proxy*) that ueue a new build using Visual Studio Team Services REST APIs
- You need to configure a Bitbucket webhook to queue a new build using the proxy. FYI webhooks "provide a way to configure Bitbucket Cloud to make requests to your server (or another external service) whenever certain events occur in Bitbucket Cloud".
- Configure a new build in VSO that gets the code from an external Git repository
*You need to use a proxy because bitbucket webhooks only do a POST to an URL without any configuration options.
Also you can create a VSO webhook to notify slack (and also the dev team) the result of the build