Deploying an application upon a Travis CI build success if functionally similar to deploying one upon a Jenkins success. All you need to do is to hook in to Scalr through its API when you build succeeds.
Using Travis CI, you can't really run arbitrary post-build shell scripts (unlike Jenkins). This makes integration a bit more complicated than using Jenkins (with Jenkins you just use the Scalr Command Line Tools to call the Scalr API), but it remains feasible.
All you need to do is have Travis CI send a notification to a Webhook Endpoint to a webapp you control (host that on your cloud infrastructure, or on e.g. Heroku), and have that webapp call the Scalr API.
Disclaimer: I work at Scalr.