ci: Continuous integration setup and badges

Description

Sets up continuous integration (CI) services for an R package that is developed on GitHub. CI services can run R CMD check automatically on various platforms, triggered by each push or pull request. These functions

Add service-specific configuration files and add them to .Rbuildignore.
Activate a service or give the user a detailed prompt.
Provide the markdown to insert a badge into README.

Usage

use_travis(browse = interactive(), ext = c("org", "com"))
use_appveyor(browse = interactive())
use_gitlab_ci()
use_circleci(browse = interactive(), image = "rocker/verse:latest")

Arguments

browse

Open a browser window to enable automatic builds for the package.

ext

which travis website to use. default to "org"for https://travis-ci.org. Change to "com" for https://travis-ci.com.

image

The Docker image to use for build. Must be available on DockerHub. The rocker/verse image includes TeX Live, pandoc, and the tidyverse packages. For a minimal image, try rocker/r-ver. To specify a version of R, change the tag from latest to the version you want, e.g. rocker/r-ver:3.5.3.

<code>use_travis()</code>

Adds a basic .travis.yml to the top-level directory of a package. This is a configuration file for the Travis CI continuous integration service.

<code>use_appveyor()</code>

Adds a basic appveyor.yml to the top-level directory of a package. This is a configuration file for the AppVeyor continuous integration service for Windows.

<code>use_gitlab_ci()</code>

Adds a basic .gitlab-ci.yml to the top-level directory of a package. This is a configuration file for the GitLab CI/CD continuous integration service for GitLab.

<code>use_circleci()</code>

Adds a basic .circleci/config.yml to the top-level directory of a package. This is a configuration file for the CircleCI continuous integration service.