Using continuous integration with Travis to keep code tested and up to date

Continuous Integration (CI) is a team programming practice that was developed to help large teams working on the same project to keep all of their code, dependencies, and tests working together as well as possible. The tools developed to facilitate this can also help us to manage our own software projects and keep on top of problems that arise from our own updates, updates in the packages we have used as dependencies, and even updates to R and the operating system in certain cases. Travis.CI is one CI service that is supported in the devtools package. With Travis.CI integrated into your project, the Travis server will build a new virtual computer, install an operating system on it, install R and all of the package dependencies your package needs, then install your package and run its test suite. Travis...