Minimal Travis-CI echo

The first thing we can do is specify some code to run in the environment. For this we need to add the script field to the YAML file with a command. A simple one would be just to echo some text.

If we make this change in the GitHub editor then immediately after you commit the change it will trigger a new build on Travis-CI. If you edit the file locally on your computer, then you need to commit the change and push it out to GitHub. In this case the push operation will trigger the build on Travis-CI.

language: minimal
script: echo Hello World