download_packages: Download packages
In RInno: An Installation Framework for Shiny Apps

Places package dependencies in pkgs_path.

1 2	download_packages(app_dir, pkgs_path, pkgs, repo, remotes, auth_user, auth_token)

`app_dir`	Development app's directory, defaults to `getwd()`.
`pkgs_path`	Default location inside the app working directory to install package dependencies This defaults to `pkgs_path = "bin"`
`pkgs`	Character vector of package dependencies. Remote development versions are supported via `remotes`. `pkgs` are downloaded into `file.path(app_dir, pkgs_path)` as Windows binary packages (.zip). If you build binary packages and store them there before calling `create_app`, they will be included as well.
`repo`	Default repository to install CRAN package dependencies. Defaults to `repo = "https://cran.rstudio.com"`.
`remotes`	Character vector of GitHub repository addresses in the format `username/repo[/subdir][\@ref\|#pull]` for GitHub package dependencies.
`auth_user`	Bitbucket username. It is recommended to create a read-only account for each app. Support for OAuth 2 and tokens is in the works.
`auth_token`	To install from a private Github repo, generate a personal access token (PAT) in https://github.com/settings/tokens and supply to this argument. This is safer than using a password because you can easily delete a PAT without affecting any others.